nano-banana-pro-openrouter

# 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 ``` uv run {baseDir}/scripts/generate_image.py \ --prompt "A cinematic sunset over snow-capped mountains" \ --filename sunset.png ``` ### Edit a single image ``` uv run {baseDir}/scripts/generate_image.py \ --prompt "Replace the sky with a dramatic aurora" \ --input-image input.jpg \ --filename aurora.png ``` ### Compose multiple images ``` uv run {baseDir}/scripts/generate_image.py \ --prompt "Combine the subjects into a single studio portrait" \ --input-image face1.jpg \ --input-image face2.jpg \ --filename composite.png ``` ## 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. --- > Converted and distributed by [TomeVault](https://tomevault.io) | [Claim this content](https://tomevault.io/claim/github/awesome-copilot) <!-- tomevault:2.0:skill_md:2026-04-05 -->