Generate & edit images using Gemini (aka "Nano Banana")


You can ask a Gemini model to generate and edit images using both text-only and text-and-image prompts. When you use Firebase AI Logic, you can make this request directly from your app.

With this capability, you can do things like:

  • Iteratively generate images through conversation with natural language, adjusting images while maintaining consistency and context.

  • Generate images with high-quality text rendering, including long strings of text.

  • Generate interleaved text-image output. For example, a blog post with text and images in a single turn. Previously, this required stringing together multiple models.

  • Generate images using Gemini's world knowledge and reasoning capabilities.

You can find a complete list of supported modalities and capabilities (along with example prompts) later on this page.

Jump to code for text-to-image Jump to code for interleaved text & images

Jump to code for image editing Jump to code for iterative image editing


See other guides for additional options for working with images
Analyze images Analyze images on-device Generate structured output

Before you begin

Click your Gemini API provider to view provider-specific content and code on this page.

If you haven't already, complete the getting started guide, which describes how to set up your Firebase project, connect your app to Firebase, add the SDK, initialize the backend service for your chosen Gemini API provider, and create a GenerativeModel instance.

For testing and iterating on your prompts, we recommend using Google AI Studio.

Models that support this capability

  • gemini-3-pro-image-preview (aka "Nano Banana Pro")
  • gemini-3.1-flash-image-preview (aka "Nano Banana 2")
  • gemini-2.5-flash-image (aka "Nano Banana")

Generate and edit images

You can generate and edit images using a Gemini model.

Generate images (text-only input)

Before trying this sample, complete the Before you begin section of this guide to set up your project and app.
In that section, you'll also click a button for your chosen Gemini API provider so that you see provider-specific content on this page.

You can ask a Gemini model to generate images by prompting with text.

Make sure to create a GenerativeModel instance, include response modalities of TEXT and IMAGE in your model configuration (or exclude TEXT if you only want image output), and call generateContent.

Swift 


import FirebaseAILogic

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
let generativeModel = FirebaseAI.firebaseAI(backend: .googleAI()).generativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [.text, .image])
)

// Provide a text prompt instructing the model to generate an image
let prompt = "Generate an image of the Eiffel tower with fireworks in the background."

// To generate an image, call `generateContent` with the text input
let response = try await model.generateContent(prompt)

// Handle the generated image
guard let inlineDataPart = response.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let uiImage = UIImage(data: inlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

Kotlin 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
val model = Firebase.ai(backend = GenerativeBackend.googleAI()).generativeModel(
    modelName = "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    generationConfig = generationConfig {
responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE) }
)

// Provide a text prompt instructing the model to generate an image
val prompt = "Generate an image of the Eiffel tower with fireworks in the background."

// To generate image output, call `generateContent` with the text input
val generatedImageAsBitmap = model.generateContent(prompt)
    // Handle the generated image
    .candidates.first().content.parts.filterIsInstance<ImagePart>().firstOrNull()?.image

Java 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI()).generativeModel(
    "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide a text prompt instructing the model to generate an image
Content prompt = new Content.Builder()
        .addText("Generate an image of the Eiffel Tower with fireworks in the background.")
        .build();

// To generate an image, call `generateContent` with the text input
ListenableFuture<GenerateContentResponse> response = model.generateContent(prompt);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) { 
        // iterate over all the parts in the first candidate in the result object
        for (Part part : result.getCandidates().get(0).getContent().getParts()) {
            if (part instanceof ImagePart) {
                ImagePart imagePart = (ImagePart) part;
                // The returned image as a bitmap
                Bitmap generatedImageAsBitmap = imagePart.getImage();
                break;
            }
        }
    }

    @Override
    public void onFailure(Throwable t) {
        t.printStackTrace();
    }
}, executor);

Web 


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, {
  model: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: {
    responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  },
});

// Provide a text prompt instructing the model to generate an image
const prompt = 'Generate an image of the Eiffel Tower with fireworks in the background.';

// To generate an image, call `generateContent` with the text input
const result = model.generateContent(prompt);

// Handle the generated image
try {
  const inlineDataParts = result.response.inlineDataParts();
  if (inlineDataParts?.[0]) {
    const image = inlineDataParts[0].inlineData;
    console.log(image.mimeType, image.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart 


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
final model = FirebaseAI.googleAI().generativeModel(
  model: 'gemini-2.5-flash-image',
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [ResponseModalities.text, ResponseModalities.image]),
);

// Provide a text prompt instructing the model to generate an image
final prompt = [Content.text('Generate an image of the Eiffel Tower with fireworks in the background.')];

// To generate an image, call `generateContent` with the text input
final response = await model.generateContent(prompt);
if (response.inlineDataParts.isNotEmpty) {
  final imageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

Unity 


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
var model = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetGenerativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
);

// Provide a text prompt instructing the model to generate an image
var prompt = "Generate an image of the Eiffel Tower with fireworks in the background.";

// To generate an image, call `GenerateContentAsync` with the text input
var response = await model.GenerateContentAsync(prompt);

var text = response.Text;
if (!string.IsNullOrWhiteSpace(text)) {
  // Do something with the text
}

// Handle the generated image
var imageParts = response.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
foreach (var imagePart in imageParts) {
  // Load the Image into a Unity Texture2D object
  UnityEngine.Texture2D texture2D = new(2, 2);
  if (texture2D.LoadImage(imagePart.Data.ToArray())) {
    // Do something with the image
  }
}

Generate interleaved images and text

Before trying this sample, complete the Before you begin section of this guide to set up your project and app.
In that section, you'll also click a button for your chosen Gemini API provider so that you see provider-specific content on this page.

You can ask a Gemini model to generate interleaved images with its text responses. For example, you can generate images of what each step of a generated recipe might look like along with the step's instructions, and you don't have to make separate requests to the model or different models.

Make sure to create a GenerativeModel instance, include response modalities of TEXT and IMAGE in your model configuration, and call generateContent.

Swift 


import FirebaseAILogic

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
let generativeModel = FirebaseAI.firebaseAI(backend: .googleAI()).generativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [.text, .image])
)

// Provide a text prompt instructing the model to generate interleaved text and images
let prompt = """
Generate an illustrated recipe for a paella.
Create images to go alongside the text as you generate the recipe
"""

// To generate interleaved text and images, call `generateContent` with the text input
let response = try await model.generateContent(prompt)

// Handle the generated text and image
guard let candidate = response.candidates.first else {
  fatalError("No candidates in response.")
}
for part in candidate.content.parts {
  switch part {
  case let textPart as TextPart:
    // Do something with the generated text
    let text = textPart.text
  case let inlineDataPart as InlineDataPart:
    // Do something with the generated image
    guard let uiImage = UIImage(data: inlineDataPart.data) else {
      fatalError("Failed to convert data to UIImage.")
    }
  default:
    fatalError("Unsupported part type: \(part)")
  }
}

Kotlin 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
val model = Firebase.ai(backend = GenerativeBackend.googleAI()).generativeModel(
    modelName = "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    generationConfig = generationConfig {
responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE) }
)

// Provide a text prompt instructing the model to generate interleaved text and images
val prompt = """
    Generate an illustrated recipe for a paella.
    Create images to go alongside the text as you generate the recipe
    """.trimIndent()

// To generate interleaved text and images, call `generateContent` with the text input
val responseContent = model.generateContent(prompt).candidates.first().content

// The response will contain image and text parts interleaved
for (part in responseContent.parts) {
    when (part) {
        is ImagePart -> {
            // ImagePart as a bitmap
            val generatedImageAsBitmap: Bitmap? = part.asImageOrNull()
        }
        is TextPart -> {
            // Text content from the TextPart
            val text = part.text
        }
    }
}

Java 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI()).generativeModel(
    "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide a text prompt instructing the model to generate interleaved text and images
Content prompt = new Content.Builder()
        .addText("Generate an illustrated recipe for a paella.\n" +
                 "Create images to go alongside the text as you generate the recipe")
        .build();

// To generate interleaved text and images, call `generateContent` with the text input
ListenableFuture<GenerateContentResponse> response = model.generateContent(prompt);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        Content responseContent = result.getCandidates().get(0).getContent();
        // The response will contain image and text parts interleaved
        for (Part part : responseContent.getParts()) {
            if (part instanceof ImagePart) {
                // ImagePart as a bitmap
                Bitmap generatedImageAsBitmap = ((ImagePart) part).getImage();
            } else if (part instanceof TextPart){
                // Text content from the TextPart
                String text = ((TextPart) part).getText();
            }
        }
    }

    @Override
    public void onFailure(Throwable t) {
        System.err.println(t);
    }
}, executor);

Web 


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, {
  model: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: {
    responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  },
});

// Provide a text prompt instructing the model to generate interleaved text and images
const prompt = 'Generate an illustrated recipe for a paella.\n.' +
  'Create images to go alongside the text as you generate the recipe';

// To generate interleaved text and images, call `generateContent` with the text input
const result = await model.generateContent(prompt);

// Handle the generated text and image
try {
  const response = result.response;
  if (response.candidates?.[0].content?.parts) {
    for (const part of response.candidates?.[0].content?.parts) {
      if (part.text) {
        // Do something with the text
        console.log(part.text)
      }
      if (part.inlineData) {
        // Do something with the image
        const image = part.inlineData;
        console.log(image.mimeType, image.data);
      }
    }
  }

} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart 


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
final model = FirebaseAI.googleAI().generativeModel(
  model: 'gemini-2.5-flash-image',
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [ResponseModalities.text, ResponseModalities.image]),
);

// Provide a text prompt instructing the model to generate interleaved text and images
final prompt = [Content.text(
  'Generate an illustrated recipe for a paella\n ' +
  'Create images to go alongside the text as you generate the recipe'
)];

// To generate interleaved text and images, call `generateContent` with the text input
final response = await model.generateContent(prompt);

// Handle the generated text and image
final parts = response.candidates.firstOrNull?.content.parts
if (parts.isNotEmpty) {
  for (final part in parts) {
    if (part is TextPart) {
      // Do something with text part
      final text = part.text
    }
    if (part is InlineDataPart) {
      // Process image
      final imageBytes = part.bytes
    }
  }
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

Unity 


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
var model = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetGenerativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
);

// Provide a text prompt instructing the model to generate interleaved text and images
var prompt = "Generate an illustrated recipe for a paella \n" +
  "Create images to go alongside the text as you generate the recipe";

// To generate interleaved text and images, call `GenerateContentAsync` with the text input
var response = await model.GenerateContentAsync(prompt);

// Handle the generated text and image
foreach (var part in response.Candidates.First().Content.Parts) {
  if (part is ModelContent.TextPart textPart) {
    if (!string.IsNullOrWhiteSpace(textPart.Text)) {
      // Do something with the text
    }
  } else if (part is ModelContent.InlineDataPart dataPart) {
    if (dataPart.MimeType == "image/png") {
      // Load the Image into a Unity Texture2D object
      UnityEngine.Texture2D texture2D = new(2, 2);
      if (texture2D.LoadImage(dataPart.Data.ToArray())) {
        // Do something with the image
      }
    }
  }
}

Edit images (text-and-image input)

Before trying this sample, complete the Before you begin section of this guide to set up your project and app.
In that section, you'll also click a button for your chosen Gemini API provider so that you see provider-specific content on this page.

You can ask a Gemini model to edit images by prompting with text and one or more images.

Make sure to create a GenerativeModel instance, include response modalities of TEXT and IMAGE in your model configuration (or exclude TEXT if you only want image output), and call generateContent.

Swift 


import FirebaseAILogic

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
let generativeModel = FirebaseAI.firebaseAI(backend: .googleAI()).generativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [.text, .image])
)

// Provide an image for the model to edit
guard let image = UIImage(named: "scones") else { fatalError("Image file not found.") }

// Provide a text prompt instructing the model to edit the image
let prompt = "Edit this image to make it look like a cartoon"

// To edit the image, call `generateContent` with the image and text input
let response = try await model.generateContent(image, prompt)

// Handle the generated image
guard let inlineDataPart = response.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let uiImage = UIImage(data: inlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

Kotlin 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
val model = Firebase.ai(backend = GenerativeBackend.googleAI()).generativeModel(
    modelName = "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    generationConfig = generationConfig {
responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE) }
)

// Provide an image for the model to edit
val bitmap = BitmapFactory.decodeResource(context.resources, R.drawable.scones)

// Provide a text prompt instructing the model to edit the image
val prompt = content {
    image(bitmap)
    text("Edit this image to make it look like a cartoon")
}

// To edit the image, call `generateContent` with the prompt (image and text input)
val generatedImageAsBitmap = model.generateContent(prompt)
    // Handle the generated text and image
    .candidates.first().content.parts.filterIsInstance<ImagePart>().firstOrNull()?.image

Java 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI()).generativeModel(
    "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide an image for the model to edit
Bitmap bitmap = BitmapFactory.decodeResource(resources, R.drawable.scones);

// Provide a text prompt instructing the model to edit the image
Content promptcontent = new Content.Builder()
        .addImage(bitmap)
        .addText("Edit this image to make it look like a cartoon")
        .build();

// To edit the image, call `generateContent` with the prompt (image and text input)
ListenableFuture<GenerateContentResponse> response = model.generateContent(promptcontent);
Futures.addCallback(response, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        // iterate over all the parts in the first candidate in the result object
        for (Part part : result.getCandidates().get(0).getContent().getParts()) {
            if (part instanceof ImagePart) {
                ImagePart imagePart = (ImagePart) part;
                Bitmap generatedImageAsBitmap = imagePart.getImage();
                break;
            }
        }
    }

    @Override
    public void onFailure(Throwable t) {
        t.printStackTrace();
    }
}, executor);

Web 


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, {
  model: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: {
    responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  },
});

// Prepare an image for the model to edit
async function fileToGenerativePart(file) {
  const base64EncodedDataPromise = new Promise((resolve) => {
    const reader = new FileReader();
    reader.onloadend = () => resolve(reader.result.split(',')[1]);
    reader.readAsDataURL(file);
  });
  return {
    inlineData: { data: await base64EncodedDataPromise, mimeType: file.type },
  };
}

// Provide a text prompt instructing the model to edit the image
const prompt = "Edit this image to make it look like a cartoon";

const fileInputEl = document.querySelector("input[type=file]");
const imagePart = await fileToGenerativePart(fileInputEl.files[0]);

// To edit the image, call `generateContent` with the image and text input
const result = await model.generateContent([prompt, imagePart]);

// Handle the generated image
try {
  const inlineDataParts = result.response.inlineDataParts();
  if (inlineDataParts?.[0]) {
    const image = inlineDataParts[0].inlineData;
    console.log(image.mimeType, image.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart 


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
final model = FirebaseAI.googleAI().generativeModel(
  model: 'gemini-2.5-flash-image',
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [ResponseModalities.text, ResponseModalities.image]),
);

// Prepare an image for the model to edit
final image = await File('scones.jpg').readAsBytes();
final imagePart = InlineDataPart('image/jpeg', image);

// Provide a text prompt instructing the model to edit the image
final prompt = TextPart("Edit this image to make it look like a cartoon");

// To edit the image, call `generateContent` with the image and text input
final response = await model.generateContent([
  Content.multi([prompt,imagePart])
]);

// Handle the generated image
if (response.inlineDataParts.isNotEmpty) {
  final imageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

Unity 


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
var model = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetGenerativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
);

// Prepare an image for the model to edit
var imageFile = System.IO.File.ReadAllBytes(System.IO.Path.Combine(
  UnityEngine.Application.streamingAssetsPath, "scones.jpg"));
var image = ModelContent.InlineData("image/jpeg", imageFile);

// Provide a text prompt instructing the model to edit the image
var prompt = ModelContent.Text("Edit this image to make it look like a cartoon.");

// To edit the image, call `GenerateContent` with the image and text input
var response = await model.GenerateContentAsync(new [] { prompt, image });

var text = response.Text;
if (!string.IsNullOrWhiteSpace(text)) {
  // Do something with the text
}

// Handle the generated image
var imageParts = response.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
foreach (var imagePart in imageParts) {
  // Load the Image into a Unity Texture2D object
  Texture2D texture2D = new Texture2D(2, 2);
  if (texture2D.LoadImage(imagePart.Data.ToArray())) {
    // Do something with the image
  }
}

Iterate and edit images using multi-turn chat

Before trying this sample, complete the Before you begin section of this guide to set up your project and app.
In that section, you'll also click a button for your chosen Gemini API provider so that you see provider-specific content on this page.

Using multi-turn chat, you can iterate with a Gemini model on the images that it generates or that you supply.

Make sure to create a GenerativeModel instance, include response modalities of TEXT and IMAGE in your model configuration (or exclude TEXT if you only want image output), and call startChat() and sendMessage() to send new user messages.

Swift 


import FirebaseAILogic

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
let generativeModel = FirebaseAI.firebaseAI(backend: .googleAI()).generativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [.text, .image])
)

// Initialize the chat
let chat = model.startChat()

guard let image = UIImage(named: "scones") else { fatalError("Image file not found.") }

// Provide an initial text prompt instructing the model to edit the image
let prompt = "Edit this image to make it look like a cartoon"

// To generate an initial response, send a user message with the image and text prompt
let response = try await chat.sendMessage(image, prompt)

// Inspect the generated image
guard let inlineDataPart = response.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let uiImage = UIImage(data: inlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

// Follow up requests do not need to specify the image again
let followUpResponse = try await chat.sendMessage("But make it old-school line drawing style")

// Inspect the edited image after the follow up request
guard let followUpInlineDataPart = followUpResponse.inlineDataParts.first else {
  fatalError("No image data in response.")
}
guard let followUpUIImage = UIImage(data: followUpInlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

Kotlin 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
val model = Firebase.ai(backend = GenerativeBackend.googleAI()).generativeModel(
    modelName = "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    generationConfig = generationConfig {
responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE) }
)

// Provide an image for the model to edit
val bitmap = BitmapFactory.decodeResource(context.resources, R.drawable.scones)

// Create the initial prompt instructing the model to edit the image
val prompt = content {
    image(bitmap)
    text("Edit this image to make it look like a cartoon")
}

// Initialize the chat
val chat = model.startChat()

// To generate an initial response, send a user message with the image and text prompt
var response = chat.sendMessage(prompt)
// Inspect the returned image
var generatedImageAsBitmap = response
    .candidates.first().content.parts.filterIsInstance<ImagePart>().firstOrNull()?.image

// Follow up requests do not need to specify the image again
response = chat.sendMessage("But make it old-school line drawing style")
generatedImageAsBitmap = response
    .candidates.first().content.parts.filterIsInstance<ImagePart>().firstOrNull()?.image

Java 


// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
GenerativeModel ai = FirebaseAI.getInstance(GenerativeBackend.googleAI()).generativeModel(
    "gemini-2.5-flash-image",
    // Configure the model to respond with text and images (required)
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide an image for the model to edit
Bitmap bitmap = BitmapFactory.decodeResource(resources, R.drawable.scones);

// Initialize the chat
ChatFutures chat = model.startChat();

// Create the initial prompt instructing the model to edit the image
Content prompt = new Content.Builder()
        .setRole("user")
        .addImage(bitmap)
        .addText("Edit this image to make it look like a cartoon")
        .build();

// To generate an initial response, send a user message with the image and text prompt
ListenableFuture<GenerateContentResponse> response = chat.sendMessage(prompt);
// Extract the image from the initial response
ListenableFuture<@Nullable Bitmap> initialRequest = Futures.transform(response, result -> {
    for (Part part : result.getCandidates().get(0).getContent().getParts()) {
        if (part instanceof ImagePart) {
            ImagePart imagePart = (ImagePart) part;
            return imagePart.getImage();
        }
    }
    return null;
}, executor);

// Follow up requests do not need to specify the image again
ListenableFuture<GenerateContentResponse> modelResponseFuture = Futures.transformAsync(
        initialRequest,
        generatedImage -> {
            Content followUpPrompt = new Content.Builder()
                    .addText("But make it old-school line drawing style")
                    .build();
            return chat.sendMessage(followUpPrompt);
        },
        executor);

// Add a final callback to check the reworked image
Futures.addCallback(modelResponseFuture, new FutureCallback<GenerateContentResponse>() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        for (Part part : result.getCandidates().get(0).getContent().getParts()) {
            if (part instanceof ImagePart) {
                ImagePart imagePart = (ImagePart) part;
                Bitmap generatedImageAsBitmap = imagePart.getImage();
                break;
            }
        }
    }

    @Override
    public void onFailure(Throwable t) {
        t.printStackTrace();
    }
}, executor);

Web 


import { initializeApp } from "firebase/app";
import { getAI, getGenerativeModel, GoogleAIBackend, ResponseModality } from "firebase/ai";

// TODO(developer) Replace the following with your app's Firebase configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
  // ...
};

// Initialize FirebaseApp
const firebaseApp = initializeApp(firebaseConfig);

// Initialize the Gemini Developer API backend service
const ai = getAI(firebaseApp, { backend: new GoogleAIBackend() });

// Create a `GenerativeModel` instance with a model that supports your use case
const model = getGenerativeModel(ai, {
  model: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: {
    responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  },
});

// Prepare an image for the model to edit
async function fileToGenerativePart(file) {
  const base64EncodedDataPromise = new Promise((resolve) => {
    const reader = new FileReader();
    reader.onloadend = () => resolve(reader.result.split(',')[1]);
    reader.readAsDataURL(file);
  });
  return {
    inlineData: { data: await base64EncodedDataPromise, mimeType: file.type },
  };
}

const fileInputEl = document.querySelector("input[type=file]");
const imagePart = await fileToGenerativePart(fileInputEl.files[0]);

// Provide an initial text prompt instructing the model to edit the image
const prompt = "Edit this image to make it look like a cartoon";

// Initialize the chat
const chat = model.startChat();

// To generate an initial response, send a user message with the image and text prompt
const result = await chat.sendMessage([prompt, imagePart]);

// Request and inspect the generated image
try {
  const inlineDataParts = result.response.inlineDataParts();
  if (inlineDataParts?.[0]) {
    // Inspect the generated image
    const image = inlineDataParts[0].inlineData;
    console.log(image.mimeType, image.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

// Follow up requests do not need to specify the image again
const followUpResult = await chat.sendMessage("But make it old-school line drawing style");

// Request and inspect the returned image
try {
  const followUpInlineDataParts = followUpResult.response.inlineDataParts();
  if (followUpInlineDataParts?.[0]) {
    // Inspect the generated image
    const followUpImage = followUpInlineDataParts[0].inlineData;
    console.log(followUpImage.mimeType, followUpImage.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart 


import 'package:firebase_ai/firebase_ai.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

await Firebase.initializeApp(
  options: DefaultFirebaseOptions.currentPlatform,
);

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
final model = FirebaseAI.googleAI().generativeModel(
  model: 'gemini-2.5-flash-image',
  // Configure the model to respond with text and images (required)
  generationConfig: GenerationConfig(responseModalities: [ResponseModalities.text, ResponseModalities.image]),
);

// Prepare an image for the model to edit
final image = await File('scones.jpg').readAsBytes();
final imagePart = InlineDataPart('image/jpeg', image);

// Provide an initial text prompt instructing the model to edit the image
final prompt = TextPart("Edit this image to make it look like a cartoon");

// Initialize the chat
final chat = model.startChat();

// To generate an initial response, send a user message with the image and text prompt
final response = await chat.sendMessage([
  Content.multi([prompt,imagePart])
]);

// Inspect the returned image
if (response.inlineDataParts.isNotEmpty) {
  final imageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

// Follow up requests do not need to specify the image again
final followUpResponse = await chat.sendMessage([
  Content.text("But make it old-school line drawing style")
]);

// Inspect the returned image
if (followUpResponse.inlineDataParts.isNotEmpty) {
  final followUpImageBytes = response.inlineDataParts[0].bytes;
  // Process the image
} else {
  // Handle the case where no images were generated
  print('Error: No images were generated.');
}

Unity 


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service
// Create a `GenerativeModel` instance with a Gemini model that supports image output
var model = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI()).GetGenerativeModel(
  modelName: "gemini-2.5-flash-image",
  // Configure the model to respond with text and images (required)
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Text, ResponseModality.Image })
);

// Prepare an image for the model to edit
var imageFile = System.IO.File.ReadAllBytes(System.IO.Path.Combine(
  UnityEngine.Application.streamingAssetsPath, "scones.jpg"));
var image = ModelContent.InlineData("image/jpeg", imageFile);

// Provide an initial text prompt instructing the model to edit the image
var prompt = ModelContent.Text("Edit this image to make it look like a cartoon.");

// Initialize the chat
var chat = model.StartChat();

// To generate an initial response, send a user message with the image and text prompt
var response = await chat.SendMessageAsync(new [] { prompt, image });

// Inspect the returned image
var imageParts = response.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
// Load the image into a Unity Texture2D object
UnityEngine.Texture2D texture2D = new(2, 2);
if (texture2D.LoadImage(imageParts.First().Data.ToArray())) {
  // Do something with the image
}

// Follow up requests do not need to specify the image again
var followUpResponse = await chat.SendMessageAsync("But make it old-school line drawing style");

// Inspect the returned image
var followUpImageParts = followUpResponse.Candidates.First().Content.Parts
                         .OfType<ModelContent.InlineDataPart>()
                         .Where(part => part.MimeType == "image/png");
// Load the image into a Unity Texture2D object
UnityEngine.Texture2D followUpTexture2D = new(2, 2);
if (followUpTexture2D.LoadImage(followUpImageParts.First().Data.ToArray())) {
  // Do something with the image
}


Configure image generation

By default, Gemini image-generation models generate square images (1:1 aspect ratio) at 1024x1024 resolution. You can customize the output of your generated images using the imageConfig property within generationConfig.

For example, you can configure the output image to be 16:9 aspect ratio and 2K resolution (resulting image of 2752x1536), like so:

Swift 

// ...

let imageConfig = ImageConfig(aspectRatio: .landscape16x9, imageSize: .size2K)
let generationConfig = GenerationConfig(
  responseModalities: [.text, .image],
  imageConfig: imageConfig
)

// Make sure you initialize your chosen Gemini API backend service
let model = FirebaseAI.firebaseAI().generativeModel(
  modelName: "gemini-3.1-flash-image-preview",
  generationConfig: generationConfig
)

// ...

Kotlin 

// ...

val config = generationConfig {
    responseModalities = listOf(ResponseModality.TEXT, ResponseModality.IMAGE)
    imageConfig = imageConfig {
        aspectRatio = AspectRatio.LANDSCAPE_16x9
        imageSize = ImageSize.SIZE_2K
    }
}

// Make sure you initialize your chosen Gemini API backend service
val model = Firebase.ai.generativeModel(
    modelName = "gemini-3.1-flash-image-preview",
    generationConfig = config
)

// ...

Java 

// ...

GenerationConfig config = new GenerationConfig.Builder()
    .setResponseModalities(Arrays.asList(ResponseModality.TEXT, ResponseModality.IMAGE))
    .setImageConfig(
        ImageConfig.builder()
            .setAspectRatio(AspectRatio.LANDSCAPE_16x9)
            .setImageSize(ImageSize.SIZE_2K)
            .build()
    )
    .build();

// Make sure you initialize your chosen Gemini API backend service
GenerativeModel model = FirebaseAI.getInstance().generativeModel(
    "gemini-3.1-flash-image-preview",
    config
);

// ...

Web 

// ...

const generationConfig = {
  responseModalities: [ResponseModality.TEXT, ResponseModality.IMAGE],
  imageConfig: {
    aspectRatio: "16:9",
    imageSize: "2K"
  }
};

// Make sure you initialize your chosen Gemini API backend service
const model = getGenerativeModel(ai, {
  model: "gemini-3.1-flash-image-preview",
  generationConfig
});

// ...

Dart 

// ...

final generationConfig = GenerationConfig(
  responseModalities: [ResponseModalities.text, ResponseModalities.image],
  imageConfig: ImageConfig(
    aspectRatio: ImageAspectRatio.landscape16x9,
    imageSize: ImageSize.size2K,
  ),
);

// Make sure you initialize your chosen Gemini API backend service
final model = FirebaseAI.instance.generativeModel(
  model: 'gemini-3.1-flash-image-preview',
  generationConfig: generationConfig,
);

// ...

Unity 

// ...

var generationConfig = new GenerationConfig(
  responseModalities: new[] { ResponseModality.Text, ResponseModality.Image },
  imageConfig: new ImageConfig(
    aspectRatio: ImageConfig.AspectRatio.Landscape16x9,
    imageSize: ImageConfig.ImageSize.Size2K)
);

// Make sure you initialize your chosen Gemini API backend service
var model = FirebaseAI.GetInstance().GetGenerativeModel(
  modelName: "gemini-3.1-flash-image-preview",
  generationConfig: generationConfig
);

// ...

Supported aspect ratios

All Gemini image-generation models support the following aspect ratios:

Default: 1:1 (square)

1:1, 1:4, 1:8, 2:3, 3:2, 3:4, 4:1, 4:3, 4:5, 5:4, 8:1, 9:16, 16:9, 21:9

Supported image sizes

Supported image sizes depend on the model you're using.

Image-generating model Supported sizes
gemini-3-pro-image-preview Default: 1024 (1K)
512, 1024 (1K), 2048 (2K), 4096 (4K)
gemini-3.1-flash-image-preview Default: 1024 (1K)
512, 1024 (1K), 2048 (2K), 4096 (4K)
gemini-2.5-flash-image Fixed at 1024 (1K)


Supported features, limitations, and best practices

Supported modalities and capabilities

The following are supported modalities and capabilities for image-generating Gemini models. Each capability shows an example prompt and has an example code sample above.

  • Text Image(s) (text-only to image)

    • Generate an image of the Eiffel tower with fireworks in the background.

  • Text Image(s) (text rendering within image)

    • Generate a cinematic photo of a large building with this giant text projection mapped on the front of the building.

  • Text Image(s) & Text (interleaved)

    • Generate an illustrated recipe for a paella. Create images alongside the text as you generate the recipe.

    • Generate a story about a dog in a 3D cartoon animation style. For each scene, generate an image.

  • Image(s) & Text Image(s) & Text (interleaved)

    • [image of a furnished room] + What other color sofas would work in my space? Can you update the image?

  • Image editing (text-and-image to image)

    • [image of scones] + Edit this image to make it look like a cartoon

    • [image of a cat] + [image of a pillow] + Create a cross stitch of my cat on this pillow.

  • Multi-turn image editing (chat)

    • [image of a blue car] + Turn this car into a convertible., then Now change the color to yellow.

Additionally, the Gemini 3 Pro Image and Gemini 3.1 Flash Image models support Grounding with Google Search.

Limitations and best practices

The following are limitations and best practices for image-output from a Gemini model.

For supported aspect ratios and resolutions for each model, see Configure image generation earlier in this guide.

  • Image-generating Gemini models support the following:

    • Generating PNG images.
    • Generating and editing images of people.
    • Using safety filters that provide a flexible and less restrictive user experience.

  • Image-generating Gemini models do not support including audio or video inputs.

  • For best performance, use the following languages:

    • Gemini 2.5 Image model: EN, es-MX, ja-JP, zh-CN, hi-IN.
    • Gemini 3 Image models: ar-EG, de-DE, EN, es-MX, fr-FR, hi-IN, id-ID, it-IT, ja-JP, ko-KR, pt-BR, ru-RU, ua-UA, vi-VN, zh-CN

  • For best results when including reference images as input:

    • Gemini 2.5 Image model: include a maximum of three images as input

    • Gemini 3 Image models: include a maximum of 14 images as input

  • When generating an image containing text, first generate the text and then generate an image with that text.

  • Image generation may not always trigger. Also, image or text generation might not work as expected in these situations:

    • The model might only generate text and no image (especially if the prompt is ambiguous). If this happens, the FinishReason is NO_IMAGE.
      Try asking for image outputs explicitly. For example, "generate an image", "provide images as you go along", "update the image".

    • The model may stop generating partway through.
      Try again or try a different prompt.

    • The model may generate text as an image.
      Try asking for text outputs explicitly. For example, "generate narrative text along with illustrations".

    • If a prompt is potentially unsafe, the model might not process the request and instead return a response indicating that it can't create unsafe images. If this happens, the FinishReason is STOP.