openrouter-gemini-image-generation

OpenRouter Gemini image generation returns 404 or 400 errors due to endpoint mismatches when using the /images/generations endpoint. Switching to the chat completions endpoint with modalities resolves these failures.

To generate images with Gemini models, call the OpenRouter /chat/completions endpoint using modalities ["image","text"] instead of /images/generations, then parse the nested response to extract the image data.

OpenRouter Gemini image generation requires validating permitted aspect ratios like "16:9" before sending requests. Using invalid aspect_ratio values with Gemini models triggers parsing errors and request failures.

Yes, you can use Nano Banana and Nano Banana Pro models for image generation on OpenRouter. These Gemini models work reliably when you apply the chat completions endpoint workaround with the modalities parameter.

The best way to fix invalid aspect_ratio errors is to bypass the /images/generations endpoint and use the chat completions endpoint with modalities, ensuring you pass only permitted aspect ratio values.

Yes, OpenRouter supports the modalities parameter for Gemini image models via the chat completions endpoint. Setting modalities to ["image","text"] provides a robust workaround for image generation endpoint failures.