Generate text using images from a local and Google Cloud Storage

This example demonstrates how to generate text using a local image and an image in Google Cloud Storage

Explore further

For detailed documentation that includes this code sample, see the following:

• Image understanding

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Go API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"
	"os"

	genai "google.golang.org/genai"
)

// generateWithMultiImg shows how to generate text using multiple image inputs.
func generateWithMultiImg(w io.Writer) error {
	ctx := context.Background()

	client, err := genai.NewClient(ctx, &genai.ClientConfig{
		HTTPOptions: genai.HTTPOptions{APIVersion: "v1"},
	})
	if err != nil {
		return fmt.Errorf("failed to create genai client: %w", err)
	}

	// TODO(Developer): Update the path to file (image source:
	//   https://storage.googleapis.com/cloud-samples-data/generative-ai/image/latte.jpg )
	imageBytes, err := os.ReadFile("./latte.jpg")
	if err != nil {
		return fmt.Errorf("failed to read image: %w", err)
	}

	contents := []*genai.Content{
		{Parts: []*genai.Part{
			{Text: "Write an advertising jingle based on the items in both images."},
			{FileData: &genai.FileData{
				// Image source: https://storage.googleapis.com/cloud-samples-data/generative-ai/image/scones.jpg
				FileURI:  "gs://cloud-samples-data/generative-ai/image/scones.jpg",
				MIMEType: "image/jpeg",
			}},
			{InlineData: &genai.Blob{
				Data:     imageBytes,
				MIMEType: "image/jpeg",
			}},
		}},
	}
	modelName := "gemini-2.5-flash"

	resp, err := client.Models.GenerateContent(ctx, modelName, contents, nil)
	if err != nil {
		return fmt.Errorf("failed to generate content: %w", err)
	}

	respText := resp.Text()

	fmt.Fprintln(w, respText)

	// Example response:
	// Okay, here's an advertising jingle inspired by the blueberry scones, coffee, flowers, chocolate cake, and latte:
	//
	// (Upbeat, jazzy music)
	// ...

	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Java API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.genai.Client;
import com.google.genai.types.Content;
import com.google.genai.types.GenerateContentResponse;
import com.google.genai.types.HttpOptions;
import com.google.genai.types.Part;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class TextGenerationWithMultiImage {

  public static void main(String[] args) throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String modelId = "gemini-2.5-flash";
    // Content from Google Cloud Storage
    String gcsFileImagePath = "gs://cloud-samples-data/generative-ai/image/scones.jpg";
    String localImageFilePath = "resources/latte.jpg";
    generateContent(modelId, gcsFileImagePath, localImageFilePath);
  }

  // Generates text with multiple images
  public static String generateContent(
      String modelId, String gcsFileImagePath, String localImageFilePath) throws IOException {
    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests.
    try (Client client =
        Client.builder()
            .location("global")
            .vertexAI(true)
            .httpOptions(HttpOptions.builder().apiVersion("v1").build())
            .build()) {

      // Read content from a local file.
      byte[] localFileImgBytes = Files.readAllBytes(Paths.get(localImageFilePath));

      GenerateContentResponse response =
          client.models.generateContent(
              modelId,
              Content.fromParts(
                  Part.fromText("Generate a list of all the objects contained in both images"),
                  Part.fromBytes(localFileImgBytes, "image/jpeg"),
                  Part.fromUri(gcsFileImagePath, "image/jpeg")),
              null);

      System.out.print(response.text());
      // Example response:
      // Okay, here's the list of objects present in both images:
      //
      // **Image 1 (Scones):**
      //
      // *   Scones
      // *   Plate
      // *   Jam/Preserve
      // *   Cream/Butter
      // *   Table/Surface
      // *   Napkin/Cloth (possibly)
      //
      // **Image 2 (Latte):**
      //
      // *   Latte/Coffee cup
      // *   Saucer
      // *   Spoon
      // *   Table/Surface
      // *   Foam/Latte art
      //
      // **Objects potentially in both (depending on interpretation and specific items):**
      //
      // *   Plate/Saucer (both are serving dishes)
      // *   Table/Surface
      return response.text();
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Node.js API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

const {GoogleGenAI} = require('@google/genai');

const GOOGLE_CLOUD_PROJECT = process.env.GOOGLE_CLOUD_PROJECT;
const GOOGLE_CLOUD_LOCATION = process.env.GOOGLE_CLOUD_LOCATION || 'global';

async function generateContent(
  projectId = GOOGLE_CLOUD_PROJECT,
  location = GOOGLE_CLOUD_LOCATION
) {
  const ai = new GoogleGenAI({
    vertexai: true,
    project: projectId,
    location: location,
  });

  const image1 = {
    fileData: {
      fileUri: 'gs://cloud-samples-data/generative-ai/image/scones.jpg',
      mimeType: 'image/jpeg',
    },
  };

  const image2 = {
    fileData: {
      fileUri: 'gs://cloud-samples-data/generative-ai/image/fruit.png',
      mimeType: 'image/png',
    },
  };

  const response = await ai.models.generateContent({
    model: 'gemini-2.5-flash',
    contents: [
      image1,
      image2,
      'Generate a list of all the objects contained in both images.',
    ],
  });

  console.log(response.text);

  return response.text;
}

Python

Before trying this sample, follow the Python setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Python API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

from google import genai
from google.genai.types import HttpOptions, Part

client = genai.Client(http_options=HttpOptions(api_version="v1"))

# Read content from GCS
gcs_file_img_path = "gs://cloud-samples-data/generative-ai/image/scones.jpg"

# Read content from a local file
with open("test_data/latte.jpg", "rb") as f:
    local_file_img_bytes = f.read()

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "Generate a list of all the objects contained in both images.",
        Part.from_uri(file_uri=gcs_file_img_path, mime_type="image/jpeg"),
        Part.from_bytes(data=local_file_img_bytes, mime_type="image/jpeg"),
    ],
)
print(response.text)
# Example response:
# Okay, here's the list of objects present in both images:
# ...

What's next

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