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gemini-2.5-flash-image (Image Edit)

Authentication

  1. Sign up for a GPTProto account at https://gptproto.com
  2. Navigate to the API Keys section in your dashboard
  3. Generate a new API key (sk-xxxxx)
  4. Copy and securely store your API key For authentication details, please refer to the Authentication section.

Initiate Request

Query Result

If the request that generated your content includes the parameter enable_sync_mode set to true (some models do not support this parameter, but you still need to query the result by id), you must call the Query Result endpoint to retrieve the final output.
After submitting your prediction request, the response will contain the id you need.
You can find it in either:
  • data.id – the unique identifier of the prediction
  • data.urls[0].get – a ready-to-use GET URL that already embeds the id

Parameters

Path Parameters

Endpoint: https://gptproto.com/api/v3/google/{model}/{scene}
Body parameters may vary depending on the scene. Incorrect scene selection may cause parameters to fail. Please choose the appropriate scene based on your actual needs.

Core Body Parameters

Advanced Body Parameters

Model Comparison

Note:
  • Gemini 3.1 Flash Image Preview: Optimized for speed and high-volume use cases. Supports 0.5K resolution and extra ultra-wide/tall aspect ratios (1:4, 4:1, 1:8, 8:1). Also supports Google Image Search Grounding.
  • Gemini 3 Pro Image Preview: Optimized for professional asset production with advanced reasoning for complex creation tasks.
  • Gemini 2.5 Flash Image: Supports a maximum of 3 reference images and 1K resolution only.

Aspect Ratio & Image Size

By default, the model keeps the output image the same size as the input image; otherwise it produces a 1:1 square. You can control the aspect ratio of the generated image with the aspect_ratio field under image_config in your request, as shown below: Gemini 2.5 Flash Image Gemini 3.1 Flash Image Preview Gemini 3 Pro Image Preview

Error Codes

Common Error Codes