Nano Banana Pro Openrouter

A straightforward wrapper around OpenRouter's Gemini 3 Pro Image model that handles the API calls and file management for you. Takes text prompts and optional input images, outputs PNG files with proper path handling and multi-image support. The resolution options (1K/2K/4K) and system prompt customization via assets/SYSTEM_TEMPLATE give you decent control without complexity. Error handling covers the usual suspects like missing API keys and rate limits. Good for when you need programmatic image generation in Claude workflows without manually wrestling with OpenRouter's API or figuring out base64 encoding.

skills.sh installs: 10K
GitHub stars: 41K
last updated: Aug 21, 2026

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Install

$ npx -y skills add github/awesome-copilot --skill nano-banana-pro-openrouter --agent claude-code

Installs into .claude/skills of the current project.

Files

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.