Nano Banana Pro Image Generation & Editing

Generate new images or edit existing ones using Google's Nano Banana Pro API (Gemini 3 Pro Image).

Usage

Run the script using absolute path (do NOT cd to skill directory first):

Generate new image:

uv run {baseDir}/scripts/generate_image.py --prompt "your image description" --filename "output-name.png" [--resolution 1K|2K|4K] [--api-key KEY]

Edit existing image:

uv run {baseDir}/scripts/generate_image.py --prompt "editing instructions" --filename "output-name.png" --input-image "path/to/input.png" [--resolution 1K|2K|4K] [--api-key KEY]

Important: Always run from the user's current working directory so images are saved where the user is working.

Default Workflow (draft > iterate > final)

• Draft (1K): quick feedback loop
• Iterate: adjust prompt in small diffs; keep filename new per run
• Final (4K): only when prompt is locked

Resolution Options

• 1K (default) - ~1024px resolution
• 2K - ~2048px resolution
• 4K - ~4096px resolution

API Key

1. --api-key argument
2. GEMINI_API_KEY environment variable

Image Editing

Use --input-image parameter with the path to the image. The prompt should contain editing instructions.

Prompt Handling

For generation: Pass user's image description as-is to --prompt. For editing: Pass editing instructions in --prompt.

Output

• Saves PNG to current directory
• Script outputs the full path to the generated image
• Do not read the image back - just inform the user of the saved path