nano-banana-pro-openrouter
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.
Source facts
- Repository
- tomevault-io/claude-code-plugins
- Last source activity
- April 6, 2026 at 07:38
- Detected SKILL.md language
- English
- Stars
- 3
- Forks
- 2
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- nano-banana-pro-openrouter
- description
- 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.
- metadata
- {"emoji":"🍌","requires":{"bins":["uv"],"env":["OPENROUTER_API_KEY"]},"primaryEnv":"OPENROUTER_API_KEY"}
# 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 | sh</code>. Windows: <code>powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | 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.
---
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