openrouter-gemini-image-generation

What problem does it solve?

OpenRouter Gemini image generation often returns 404 or 400 errors, especially with Nano Banana and Gemini image models, due to endpoint mismatches and invalid aspect_ratio handling. This Skill provides a robust workaround by switching the workflow to the chat completions endpoint with modalities to reliably generate images and properly parse responses.

Core Features & Use Cases

• Endpoint workaround: Use /chat/completions with modalities to generate images instead of /images/generations.
• Model compatibility: Supports Gemini image models (e.g., Nano Banana Pro and Nano Banana) and their edge cases.
• Input validation & parsing: Validates allowed aspect ratios and parses the nested response to extract image data for downstream use.

Quick Start

To generate an image, call the chat completions endpoint with modalities ["image","text"] and model "google/gemini-3-pro-image-preview" (or "google/gemini-2.5-flash-image"), ensuring aspect_ratio is a permitted value such as "16:9".