从 Imagen 迁移到 Gemini 图片模型(“Nano Banana”)


所有 Imagen 模型均已弃用,最早将于 2026 年 8 月 17 日关停 。此弃用和关停适用于 整个 Google,并且适用于 Gemini Developer APIAgent Platform Gemini API (formerly Vertex AI)

在此关停日期之前,为避免服务中断,您应按照本指南中的说明,将 应用从使用 Imagen 模型迁移到使用 Gemini 3.x Image 模型 (“Nano Banana”模型)。

如果您有与此弃用和关停相关的紧急问题, 请与 Firebase 支持团队联系

替代 Gemini 图片模型

请查看下表,为您的应用选择替代 Gemini 3.x Image 模型。

Imagen 模型 Gemini 3.x Image 模型(“Nano Banana”)
imagen-4.0-fast-generate-001 gemini-3.1-flash-image(思考等级为 MINIMAL
imagen-4.0-generate-001 gemini-3.1-flash-image(思考等级为 HIGH
imagen-4.0-ultra-generate-001 gemini-3-pro-image
imagen-3.0-capability-001 gemini-3.1-flash-image

迁移您的应用

本部分展示了从 Imagen 模型迁移到 Gemini 图片模型之前和之后的示例。

根据文字生成图片

点击您的 Gemini API 提供商,以查看此页面上特定于提供商的内容 和代码。

如需根据文字生成图片,请通过进行以下更改来迁移应用:

  • 使用适当的 替代 Gemini 图片模型 (例如 gemini-3.1-flash-image)。

  • 创建 GenerativeModel 实例(而不是 ImagenModel 实例)。

  • 更新 模型配置选项 以适应 Gemini 图片模型。

    • 在此配置中,将响应模式设置为 IMAGE。请注意,
      Gemini图片模型可以配置为同时返回 图片文本。

Swift

之前


import FirebaseAILogic

// Initialize the Gemini Developer API backend service.
let ai = FirebaseAI.firebaseAI(backend: .googleAI())

// Create an `ImagenModel` instance with a model that supports your use case.
let model = ai.imagenModel(modelName: "IMAGEN_MODEL_NAME")

// Provide an image generation prompt.
let prompt = "An astronaut riding a horse"

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

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

之后


import FirebaseAILogic

// Initialize the Gemini Developer API backend service.
let ai = FirebaseAI.firebaseAI(backend: .googleAI())

// Create a `GenerativeModel` instance with a Gemini model that supports image output.
let model = ai.generativeModel(
  modelName: "GEMINI_IMAGE_MODEL_NAME",
  generationConfig: GenerationConfig(
    responseModalities: [.image],
    imageConfig: ImageConfig(aspectRatio: .landscape4x3)
  )
)

// Provide an image generation prompt.
let prompt = "An astronaut riding a horse"

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

// Handle the case where no images were generated.
guard let inlineDataPart = response.inlineDataParts.first else {
  fatalError("No image in the response.")
}

// Process the image.
guard let uiImage = UIImage(data: inlineDataPart.data) else {
  fatalError("Failed to convert data to UIImage.")
}

Kotlin

之前


// Initialize the Gemini Developer API backend service.
val ai = Firebase.ai(backend = GenerativeBackend.googleAI())

// Create an `ImagenModel` instance with an Imagen model that supports your use case.
val model = ai.imagenModel("IMAGEN_MODEL_NAME")

// Provide an image generation prompt.
val prompt = "An astronaut riding a horse"

// To generate an image, call `generateImages` with the text prompt.
val imageResponse = model.generateImages(prompt)

// Handle the generated image.
val image = imageResponse.images.first()

val bitmapImage = image.asBitmap()

之后


// Initialize the Gemini Developer API backend service.
val ai = Firebase.ai(backend = GenerativeBackend.googleAI())

// Create a `GenerativeModel` instance with a Gemini model that supports image output.
val model = ai.generativeModel(
    modelName = "GEMINI_IMAGE_MODEL_NAME",
    generationConfig = generationConfig {
      responseModalities = listOf(ResponseModality.IMAGE),
      imageConfig = imageConfig {
        aspectRatio = AspectRatio.LANDSCAPE_4x3
      }
    }
)

// Provide an image generation prompt.
val prompt = "An astronaut riding a horse"

// To generate an image, call `generateContent` with the text prompt.
val imageResponse = model.generateContent(prompt)

if (imageResponse.finishReason == FinishReason.NO_IMAGE) {
  // Handle the case where no images were generated.
} else {
  // Handle the generated image.
  val bitmapImage = imageResponse.candidates.first().content.parts.filterIsInstance().firstOrNull()?.image
}

Java

之前


// Initialize the Gemini Developer API backend service.
// Create an `ImagenModel` instance with an Imagen model that supports your use case.
ImagenModel imagenModel = FirebaseAI.getInstance(GenerativeBackend.googleAI())
        .imagenModel(
                /* modelName */ "IMAGEN_MODEL_NAME");

ImagenModelFutures model = ImagenModelFutures.from(imagenModel);

// Provide an image generation prompt.
String prompt = "An astronaut riding a horse";

// To generate an image, call `generateImages` with the text prompt.
Futures.addCallback(model.generateImages(prompt), new FutureCallback<ImagenGenerationResponse>() {
    @Override
    public void onSuccess(ImagenGenerationResponse result) {
        if (result.getImages().isEmpty()) {
            Log.d("TAG", "No images generated");
        }
        Bitmap bitmap = result.getImages().get(0).asBitmap();
        // Use the bitmap to display the image in your UI.
    }

    @Override
    public void onFailure(Throwable t) {
        // ...
    }
}, Executors.newSingleThreadExecutor());

之后


// 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_IMAGE_MODEL_NAME",
    new GenerationConfig.Builder()
        .setResponseModalities(Arrays.asList(ResponseModality.IMAGE))
        .setImageConfig(new ImageConfig(AspectRatio.LANDSCAPE_4x3, null))
        .build()
);

GenerativeModelFutures model = GenerativeModelFutures.from(ai);

// Provide a text prompt instructing the model to generate an image.
Content prompt = new Content.Builder()
        .addText("An astronaut riding a horse")
        .build();

// To generate an image, call `generateContent` with the text input.
Executor executor = Executors.newSingleThreadExecutor();
ListenableFuture response = model.generateContent(prompt);
Futures.addCallback(response, new FutureCallback() {
    @Override
    public void onSuccess(GenerateContentResponse result) {
        if (result.finishReason == FinishReason.NO_IMAGE) {
            // handle the case where no images were generated
            return;
        }
        // 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

之前


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

// TODO(developer): Replace the following with your app's Firebase configuration
const firebaseConfig = {
  // ...
};

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

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

// Create an `ImagenModel` instance with an Imagen model that supports your use case.
const model = getImagenModel(ai, { model: "IMAGEN_MODEL_NAME" });

// Provide an image generation prompt.
const prompt = "An astronaut riding a horse.";

// To generate an image, call `generateImages` with the text prompt.
const response = await model.generateImages(prompt)

// If fewer images were generated than were requested,
// then `filteredReason` will describe the reason they were filtered out.
if (response.filteredReason) {
  console.log(response.filteredReason);
}

if (response.images.length == 0) {
  throw new Error("No images in the response.")
}

const image = response.images[0];

之后


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

// TODO(developer): Replace the following with your app's Firebase configuration
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_IMAGE_MODEL_NAME",
  generationConfig: {
    responseModalities: [ResponseModality.IMAGE],
    imageConfig: {
      aspectRatio: ImageConfigAspectRatio.LANDSCAPE_4x3
    }
  },
});

// Provide an image generation prompt.
const prompt = "An astronaut riding a horse.";

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

// Handle the generated image.
try {
  const response = result.response;
  if (response.candidates?.[0].finishReason == FinishReason.NO_IMAGE) {
    // Handle the case where no images were generated.
  }
  const inlineDataParts = response.inlineDataParts();
  if (inlineDataParts?.[0]) {
    const image = inlineDataParts[0].inlineData;
    // Use this mimeType and base64 data to display the image using your preferred tooling.
    console.log(image.mimeType, image.data);
  }
} catch (err) {
  console.error('Prompt or candidate was blocked:', err);
}

Dart

之前


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

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

// Initialize the Gemini Developer API backend service.
final ai = FirebaseAI.googleAI();

// Create an `ImagenModel` instance with an Imagen model that supports your use case.
final model = ai.imagenModel(model: 'IMAGEN_MODEL_NAME');

// Provide an image generation prompt.
const prompt = 'An astronaut riding a horse.';

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

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

之后


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

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

// Initialize the Gemini Developer API backend service.
final ai = FirebaseAI.googleAI();

// Create a `GenerativeModel` instance with a Gemini model that supports image output.
final model = ai.generativeModel(
  model: 'GEMINI_IMAGE_MODEL_NAME',
  generationConfig: GenerationConfig(
    responseModalities: [ResponseModalities.image],
    imageConfig: ImageConfig(aspectRatio: ImageAspectRatio.landscape4x3)
  ),
);

// Provide a text prompt instructing the model to generate an image.
final prompt = [Content.text('An astronaut riding a horse.')];

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

Unity

之前


using Firebase.AI;

// Initialize the Gemini Developer API backend service
var ai = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI());

// Create an `ImagenModel` instance with a model that supports your use case
var model = ai.GetImagenModel(modelName: "IMAGEN_MODEL_NAME");

// Provide an image generation prompt
var prompt = "An astronaut riding a horse";

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

// Handle the generated image
if (response.Images.Count == 0) {
  throw new Exception("No image in the response.");
}
var image = response.Images[0].AsTexture2D();

之后


using Firebase;
using Firebase.AI;

// Initialize the Gemini Developer API backend service.
var ai = FirebaseAI.GetInstance(FirebaseAI.Backend.GoogleAI());

// Create a `GenerativeModel` instance with a Gemini model that supports image output.
var model = ai.GetGenerativeModel(
  modelName: "GEMINI_IMAGE_MODEL_NAME",
  generationConfig: new GenerationConfig(
    responseModalities: new[] { ResponseModality.Image },
    imageConfig: new ImageConfig(aspectRatio: ImageConfig.AspectRatio.Landscape4x3)
  )
);

// Provide an image generation prompt.
var prompt = "An astronaut riding a horse";

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

if (response.Candidates.First().