# Ccskill Nanobanana

> Skill for image generation needs. Generate and edit high-quality images via Google Nano Banana (Gemini Image API). Two models: Nano Banana 2 Lite (fast, low-cost, default) and Nano Banana Pro (high-resolution, dense text, complex instruction following). Supports logos, infographics, illustrations, photorealistic images, and more.

- Skill: `feedtailor/ccskill-nanobanana` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add feedtailor/ccskill-nanobanana`
- Raw SKILL.md: https://api.skillmd.com/api/skills/feedtailor/ccskill-nanobanana/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: feedtailor (https://skillmd.com/u/feedtailor)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/feedtailor/ccskill-nanobanana

---


# ccskill-nanobanana — Nano Banana Image Generation Skill

## Overview

This skill generates images with the Google Nano Banana family (Gemini Image API).
The user states their intent ("I want a hero image for my blog post"); Claude picks
the model, crafts a structured prompt, chooses parameters, and runs the command.
Users are not expected to write prompts themselves.

Sister skill: `ccskill-gptimage` (OpenAI gpt-image-2). If both are installed, see
"Sister skill comparison" below for which to reach for first.

## Prerequisites

- The repository is installed via `./install.sh`, which registers the
  `ccskill-nanobanana` command in `~/.local/bin`.
- If the command is not on PATH, fall back to the venv directly:
  `$CCSKILL_NANOBANANA_DIR/venv/bin/python $CCSKILL_NANOBANANA_DIR/generate_image.py "prompt"`
- A Gemini API key must be configured (`GEMINI_API_KEY` env var, or `.env` in the
  repository root). Get one at https://aistudio.google.com/apikey
- If anything fails, run `ccskill-nanobanana doctor` to diagnose.

## Usage

```bash
ccskill-nanobanana generate "prompt" [options...]
```

### Options

| Option | Description | Default | Choices |
|--------|-------------|---------|---------|
| `--model` | Model to use | `lite` | `lite`, `pro`, or any Gemini image model ID |
| `--resolution` | Output resolution | lite: `1K` / pro: `2K` | `1K`, `2K`, `4K` (lite supports 1K only) |
| `--aspect` | Aspect ratio | `16:9` | `1:1`, `16:9`, `9:16`, `4:3`, `3:2`, etc. |
| `--output` | Output directory | `./generated_images` | any path |
| `--reference` | Reference image(s), repeatable | none | image file path (up to 14) |

### Model Selection

| | Nano Banana 2 Lite (`lite`) | Nano Banana Pro (`pro`) |
|---|---|---|
| Model ID | `gemini-3.1-flash-lite-image` | `gemini-3-pro-image` |
| Cost (approx.) | ~$0.034 / image (1K) | ~$0.134 (1K/2K) – $0.24 (4K) / image |
| Resolution | 1K only | 1K / 2K / 4K |
| Speed | Lightning fast | Slower ("thinking" model) |
| Best for | Everyday images, iteration, drafts, illustrations, photos | Dense text, complex infographics, 2K/4K output, strict multi-reference composition |

**Default to `lite`.** Switch to `pro` when the request needs:
- 2K/4K resolution output
- Long or dense legible text (infographics, posters with paragraphs)
- Complex multi-step instruction following or strict layout control

### Examples

Basic generation (lite, 1K):
```bash
ccskill-nanobanana generate "a cat playing piano in watercolor style"
```

High-resolution wide image with Pro:
```bash
ccskill-nanobanana generate "sunset coastline, cinematic" --model pro --resolution 4K --aspect 16:9
```

Edit with reference images:
```bash
ccskill-nanobanana generate "change background to sunset" --reference ./original.png
ccskill-nanobanana generate "draw this person in this pose" --reference ./person.png --reference ./pose.png
```

Reference image use cases: partial editing (background, colors), style transfer,
character consistency, image compositing.

## Prompting Guides (read before crafting prompts)

Pick the guide matching the selected model and Read it when crafting non-trivial prompts:

- **Lite** (default): [guides/prompting-lite.md](guides/prompting-lite.md) —
  5 core components (Style/Subject/Setting/Action/Composition), editing
  strategies, fast-iteration workflow.
- **Pro**: [guides/prompting-pro.md](guides/prompting-pro.md) — Creative
  Director approach, text rendering & infographics, identity locking,
  structural control, 2D→3D.

Universal principles (both models):
- Use natural language and full sentences, not keyword soups.
- Be specific: subject, setting, lighting, mood, materiality.
- When editing, state the change directly ("change the tie to green").
- For text in images, put the exact string in quotes and describe typography.

## Output

- Images are saved to the output directory (default: `./generated_images`),
  filename is a timestamp (e.g., `20260702_153045.png`); the extension is
  auto-detected from the API response (PNG/JPEG/WebP).
- A JSON metadata sidecar `{image}.json` is written next to each image,
  recording model, prompt, resolution, aspect ratio, and reference images.
- Every image is also stocked into the user-wide gallery store
  (`~/.ccskill-nanobanana/gallery/`, override with `CCSKILL_NANOBANANA_GALLERY_DIR`),
  regardless of which project it was generated from.

## Browsing Generated Images

```bash
ccskill-nanobanana browse            # delegates to ccskill-gallery if installed
ccskill-nanobanana browse --port 9000
ccskill-nanobanana browse --bind 0.0.0.0   # for remote-dev: view from another machine
```

`browse` has no built-in viewer. If [ccskill-gallery](https://github.com/feedtailor/ccskill-gallery)
is installed, it launches that (a cross-skill viewer that also covers
ccskill-omniflash and ccskill-gptimage output); `--port`/`--bind`/`--no-open`
are passed through as-is. If it isn't installed, `browse` just prints where
the files live — the gallery store itself is always written to regardless.

## Sister skill comparison (vs ccskill-gptimage)

| Use case | First choice |
|---|---|
| Fast, cheap everyday generation & iteration | nanobanana (lite) |
| Dense Japanese/multilingual text, complex instructions | gptimage or nanobanana (pro) — compare |
| 2K/4K high-resolution output | nanobanana (pro) |
| Transparent background | nanobanana (gptimage's gpt-image-2 cannot) |
| Reference-image fidelity with masks | gptimage (supports --mask) |

## Notes

- Nano Banana is a paid API; charges apply per image. Prefer `lite` unless the
  task needs Pro (see Model Selection).
- Generated images include a SynthID watermark.
- Verify factual accuracy of generated diagrams/infographics before use.

## Troubleshooting

Run `ccskill-nanobanana doctor` first. Common issues:

| Symptom | Fix |
|---|---|
| `command not found: ccskill-nanobanana` | `cd <repo> && ./install.sh`, ensure `~/.local/bin` is in PATH |
| API error mentioning key | Configure `GEMINI_API_KEY` (env or repo `.env`) |
| `モデル ... は解像度 ... に対応していません` | lite is 1K-only; drop `--resolution` or use `--model pro` |
| Old skill `nano-banana-pro` still appears | Re-run `./install.sh` (it migrates the old registration) |