nano-banana-pro

Name: nano-banana-pro
Author: intellectronica

Text-to-image generation and image-to-image editing via Google's Gemini 3 Pro Image API. Supports both new image generation from text prompts and editing of existing images with instruction-based modifications Configurable output resolution: 1K (default), 2K, or 4K for high-resolution results Automatically detects API key from --api-key argument or GEMINI_API_KEY environment variable Saves PNG output to the user's current working directory with timestamped filenames

INSTALLATION

npx skills add https://github.com/intellectronica/agent-skills --skill nano-banana-pro

Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

$2c

Resolution Options

The Gemini 3 Pro Image API supports three resolutions (uppercase K required):

1K (default) - ~1024px resolution

2K - ~2048px resolution

4K - ~4096px resolution

Map user requests to API parameters:

No mention of resolution → 1K

"low resolution", "1080", "1080p", "1K" → 1K

"2K", "2048", "normal", "medium resolution" → 2K

"high resolution", "high-res", "hi-res", "4K", "ultra" → 4K

API Key

The script checks for API key in this order:

--api-key argument (use if user provided key in chat)

GEMINI_API_KEY environment variable

If neither is available, the script exits with an error message.

Filename Generation

Generate filenames with the pattern: yyyy-mm-dd-hh-mm-ss-name.png

Format: {timestamp}-{descriptive-name}.png

Timestamp: Current date/time in format yyyy-mm-dd-hh-mm-ss (24-hour format)

Name: Descriptive lowercase text with hyphens

Keep the descriptive part concise (1-5 words typically)

Use context from user's prompt or conversation

If unclear, use random identifier (e.g., x9k2, a7b3)

Examples:

Prompt "A serene Japanese garden" → 2025-11-23-14-23-05-japanese-garden.png

Prompt "sunset over mountains" → 2025-11-23-15-30-12-sunset-mountains.png

Prompt "create an image of a robot" → 2025-11-23-16-45-33-robot.png

Unclear context → 2025-11-23-17-12-48-x9k2.png

Image Editing

When the user wants to modify an existing image:

Check if they provide an image path or reference an image in the current directory

Use --input-image parameter with the path to the image

The prompt should contain editing instructions (e.g., "make the sky more dramatic", "remove the person", "change to cartoon style")

Common editing tasks: add/remove elements, change style, adjust colors, blur background, etc.

Prompt Handling

For generation: Pass user's image description as-is to --prompt. Only rework if clearly insufficient.

For editing: Pass editing instructions in --prompt (e.g., "add a rainbow in the sky", "make it look like a watercolor painting")

Preserve user's creative intent in both cases.

Output

Saves PNG to current directory (or specified path if filename includes directory)

Script outputs the full path to the generated image

Do not read the image back - just inform the user of the saved path

Examples

Generate new image:

uv run ~/.claude/skills/nano-banana-pro/scripts/generate_image.py --prompt "A serene Japanese garden with cherry blossoms" --filename "2025-11-23-14-23-05-japanese-garden.png" --resolution 4K

Edit existing image:

uv run ~/.claude/skills/nano-banana-pro/scripts/generate_image.py --prompt "make the sky more dramatic with storm clouds" --filename "2025-11-23-14-25-30-dramatic-sky.png" --input-image "original-photo.jpg" --resolution 2K