nano-banana-pro

Use it when: you want an image made from a description, or an existing image changed with an instruction
It does: runs a bundled script that calls Google's Gemini 3 Pro Image model, also called Nano Banana Pro
You get: a PNG with a timestamped name in your working folder, at about 1024, 2048 or 4096 pixels (1K, 2K or 4K)
Workflow: drafts at the smallest size while the prompt changes, and renders the largest only once it's settled
Needs: uv and a Gemini API key; the commands point at Codex's skills folder, so other agents need the path adjusted

TLDR

The agent runs one Python script with uv, passing your description as the prompt, or an edit instruction plus an input image to change a picture you have: remove a person, make the sky stormier, turn it into a watercolor. It passes your words through as they are unless they're clearly too thin, and has templates for vague requests and for precise edits that say "change only this, keep everything else identical". Size follows what you say: nothing or "1080p" gives the smallest, "medium" the middle one, "high-res" or "4K" the largest. Files are named by date, time and a few descriptive words and saved where you're working, and the agent tells you the path rather than opening the image. It also lists quick fixes for a missing key, a wrong image path and quota errors.

Summarizes the skill at aca4fea.

openclaw skills install @steipete/nano-banana-pro

ClawHub page · All skills from clawhub.ai/steipete

Downloads: 106,938 on ClawHub, Sep 21, 2026
Downloads: 132,765 on Tencent SkillHub, Sep 21, 2026

Category	category:media Generate and edit video, images and audio.
Type	type:tool Operates a CLI, API, app or bundled script to get something done.
Effect	effect:local Its own steps create or change files, git state or local tools.
Needs	needs:account An account, API key or paid plan with an outside service.
Publisher	by:official A verified publisher on its registry (skills.sh, ClawHub or Tencent SkillHub), or the company or maintainer behind the product the skill operates.
Topics	image ai-generation
Stack	stack:gemini

SKILL.md

From ClawHub, version 1.0.1. Checked daily, last changed Oct 20, 2026.

Frontmatter

name: nano-banana-pro
description: Generate/edit images with Nano Banana Pro (Gemini 3 Pro Image). Use for image create/modify requests incl. edits. Supports text-to-image + image-to-image; 1K/2K/4K; use --input-image.

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 ~/.codex/skills/nano-banana-pro/scripts/generate_image.py --prompt "your image description" --filename "output-name.png" [--resolution 1K|2K|4K] [--api-key KEY]

Edit existing image:

uv run ~/.codex/skills/nano-banana-pro/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, not in the skill directory.

Default Workflow (draft → iterate → final)

Goal: fast iteration without burning time on 4K until the prompt is correct.

Draft (1K): quick feedback loop
- uv run ~/.codex/skills/nano-banana-pro/scripts/generate_image.py --prompt "<draft prompt>" --filename "yyyy-mm-dd-hh-mm-ss-draft.png" --resolution 1K
Iterate: adjust prompt in small diffs; keep filename new per run
- If editing: keep the same --input-image for every iteration until you’re happy.
Final (4K): only when prompt is locked
- uv run ~/.codex/skills/nano-banana-pro/scripts/generate_image.py --prompt "<final prompt>" --filename "yyyy-mm-dd-hh-mm-ss-final.png" --resolution 4K

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.

Preflight + Common Failures (fast fixes)

Preflight:
- command -v uv (must exist)
- test -n \"$GEMINI_API_KEY\" (or pass --api-key)
- If editing: test -f \"path/to/input.png\"
Common failures:
- Error: No API key provided. → set GEMINI_API_KEY or pass --api-key
- Error loading input image: → wrong path / unreadable file; verify --input-image points to a real image
- “quota/permission/403” style API errors → wrong key, no access, or quota exceeded; try a different key/account

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.

Prompt Templates (high hit-rate)

Use templates when the user is vague or when edits must be precise.

Generation template:
- “Create an image of: <subject>. Style: <style>. Composition: <camera/shot>. Lighting: <lighting>. Background: <background>. Color palette: <palette>. Avoid: <list>.”
Editing template (preserve everything else):
- “Change ONLY: <single change>. Keep identical: subject, composition/crop, pose, lighting, color palette, background, text, and overall style. Do not add new objects. If text exists, keep it unchanged.”

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 ~/.codex/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 ~/.codex/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