nano-banana-pro

name	nano-banana-pro
description	Generate or edit images with Google's Nano Banana Pro image model through the bundled Gemini API script. Use for text-to-image generation, image-to-image edits, or requests for 1K, 2K, or 4K Gemini image output.

Nano Banana Pro

Generate or edit images with the bundled script. Resolve the script relative to this SKILL.md; do not assume a particular agent harness or installed-skills directory.

Preflight

Run the non-billing check before the first generation in a session:

uv run /absolute/path/to/nano-banana-pro/scripts/generate_image.py --check

The script reads GEMINI_API_KEY from the environment. If this machine keeps the key in ~/.secrets, source that file without printing its contents:

source ~/.secrets >/dev/null 2>&1
uv run /absolute/path/to/nano-banana-pro/scripts/generate_image.py --check

Never echo a key. Prefer GEMINI_API_KEY over --api-key, because command-line arguments may be visible to other processes.

Generate

Run from the user's working directory so relative output paths land with the rest of their work:

uv run /absolute/path/to/nano-banana-pro/scripts/generate_image.py \
  --prompt "A serene Japanese garden with cherry blossoms" \
  --filename "2026-07-25-09-30-00-japanese-garden.png" \
  --resolution 1K

Use the filename format yyyy-mm-dd-hh-mm-ss-description.png. Keep a new filename for every iteration.

Start at 1K. Move to 2K when normal-resolution output is requested and to 4K only for a requested or approved final high-resolution result. Dimensions map as follows:

• low resolution, 1080p, or 1K: 1K
• normal, medium, 2048, or 2K: 2K
• high resolution, high-res, ultra, or 4K: 4K

Edit

Pass the source image with --input-image:

uv run /absolute/path/to/nano-banana-pro/scripts/generate_image.py \
  --input-image "/absolute/path/to/original.jpg" \
  --prompt "Change only the sky to dramatic storm clouds; preserve the subject, crop, lighting, text, and all other details." \
  --filename "2026-07-25-09-35-00-dramatic-sky.png" \
  --resolution 2K

For precise edits, name the single change and explicitly list what must remain unchanged. Reuse the same original input while iterating unless the user asks to build on an earlier generated result.

Output and Errors

The script creates parent directories as needed, writes a PNG, and prints its absolute path. Inspect the image before handing it off when visual quality is part of the request.

Common failures:

• No API key provided: load GEMINI_API_KEY.
• Error loading input image: verify the source path and permissions.
• quota, permission, or HTTP 403 errors: the configured account lacks access or quota; do not expose or guess credentials.