Runway Image Generation API

The Runway Image Generation API provides text-to-image generation using the Gen-4 Image and Gemini 3 Pro Image models. Accepts text prompts up to 1000 characters and supports multiple aspect ratios. Also includes task status polling. Uses the same asynchronous task pattern and Bearer token authentication as the video API. As of April 2026, Gemini 3 Pro Image supports up to 5,500-character prompts and 14 reference images.