Generate or edit images via OpenRouter with the Gemini 3 Pro Image model. Use for prompt-only image generation, image edits, and multi-image compositing; supports 1K/2K/4K output.

Nano Banana Pro OpenRouter Overview Generate or edit images with OpenRouter using the google/gemini 3 pro image preview model. Support prompt only generation, single image edits, and multi image composition. Prompt only generation Edit a single image Compose multiple images Resolution Use resolution with 1K , 2K , or 4K . Default is 1K if not specified. System prompt customization The skill reads an optional system prompt from assets/SYSTEM TEMPLATE . This allows you to customize the image generation behavior without modifying code. Behavior and constraints Accept up to 3 input images via repeated input image . filename accepts relative paths (saves to current directory) or absolute paths. If multiple images are returned, append 1 , 2 , etc. to the filename. Print MEDIA: <path for each saved image. Do not read images back into the response. Troubleshooting If the script exits non zero, check stderr against these common blockers: Symptom Resolution OPENROUTER API KEY is not set Ask the user to set it. PowerShell: $env:OPENROUTER API KEY = "sk or ..." / bash: export OPENROUTER API KEY="sk or ..." uv: command not found or not recognized macOS/Linux: <code curl LsSf https://astral.sh/uv/install.sh & 124; sh</code . Windows: <code powershell ExecutionPolicy ByPass c "irm https://astral.sh/uv/install.ps1 & 124; iex"</code . Then restart the terminal. AuthenticationError / HTTP 401 Key is invalid or has no credits. Verify at <https://openrouter.ai/settings/keys . For transient errors (HTTP 429, network timeouts), retry once after 30 seconds. Do not retry the same error more than twice — surface the issue to the user instead.

nano-banana-pro-openrouter