Nano Banana

---
name: nano-banana
description: REQUIRED for all image generation requests. Generate and edit images using Nano Banana (Gemini CLI). Handles blog featured images, YouTube thumbnails, icons, diagrams, patterns, illustrations, photos, visual assets, graphics, artwork, pictures. Also routes specialty creative recipes (anime-to-life, character-reference-sheet, figure-to-life, imax-portrait, j-cover, j-idol, j-poses, photo-restoration, real-mecha). Use this skill whenever the user asks to create, generate, make, draw, design, or edit any image or visual content.
allowed-tools: Bash(gemini:*)
version: 1.0.0
category: utility
---

# Nano Banana Image Generation

Generate professional images via the Gemini CLI's nanobanana extension. This skill is both the generic image-generation surface AND the router for specialty creative recipes.

## When to Use This Skill

ALWAYS use this skill when the user:
- Asks for any image, graphic, illustration, or visual
- Wants a thumbnail, featured image, or banner
- Requests icons, diagrams, or patterns
- Asks to edit, modify, or restore a photo
- Uses words like: generate, create, make, draw, design, visualize
- Names one of the specialty recipes below (e.g. "make this an IMAX portrait", "j-idol gravure", "real mecha")

Do NOT attempt to generate images through any other method.

## Specialty Recipes (load on demand)

When the user's request matches one of these recipes — by name or by intent — call
`get_skill_file(name="nano-banana", path="references/<recipe>.md")` on `gobby-skills` and
follow that file's instructions, then generate via the commands below.

| Recipe | Use when the user asks for… |
|--------|------------------------------|
| `anime-to-life` | Turning anime/art/3D characters into photorealistic cosplayer photos |
| `character-reference-sheet` | A 3-column character sheet (portrait + front + back) in a matching style |
| `figure-to-life` | Converting a figure/statue/toy photo into a photorealistic human cosplayer |
| `imax-portrait` | Recomposing a portrait into 1.43:1 IMAX 70mm framing with bokeh and grain |
| `j-cover` | Turning a character image into a Japanese magazine cover with bilingual typography |
| `j-idol` | Photorealistic J-Idol gravure portrait (2:3 knee-up, dreamy bokeh, rim light) |
| `j-poses` | A pose library to mix into other prompts (silhouette/line/mood reference) |
| `photo-restoration` | Restoring blurry/vintage photos to clean 8k while preserving identity |
| `real-mecha` | Converting 2D mecha art into a photorealistic hard-surface render |

If the request doesn't match a specialty recipe, skip this section and use the generic commands below.

If `get_skill_file` returns `{"success": false, ...}`, surface the error to the user and fall back to generic generation.

## Before First Use

1. Verify extension is installed:

   ```bash
   gemini extensions list | grep nanobanana
   ```

2. If missing, install it:

   ```bash
   gemini extensions install https://github.com/gemini-cli-extensions/nanobanana
   ```

3. Verify API key is set:

   ```bash
   [ -n "$GEMINI_API_KEY" ] && echo "API key configured" || echo "Missing GEMINI_API_KEY"
   ```

## Command Selection

| User Request | Command |
|--------------|---------|
| "make me a blog header" | `/generate` |
| "create an app icon" | `/icon` |
| "draw a flowchart of..." | `/diagram` |
| "fix this old photo" | `/restore` |
| "remove the background" | `/edit` |
| "create a repeating texture" | `/pattern` |
| "make a comic strip" | `/story` |

## Available Commands

**Note:** Always use the `--yolo` flag to automatically approve all tool actions.

| Command | Use Case |
|---------|----------|
| `gemini --yolo "/generate 'prompt'"` | Text-to-image generation |
| `gemini --yolo "/edit file.png 'instruction'"` | Modify existing image |
| `gemini --yolo "/restore old_photo.jpg 'fix scratches'"` | Repair damaged photos |
| `gemini --yolo "/icon 'description'"` | App icons, favicons, UI elements |
| `gemini --yolo "/diagram 'description'"` | Flowcharts, architecture diagrams |
| `gemini --yolo "/pattern 'description'"` | Seamless textures and patterns |
| `gemini --yolo "/story 'description'"` | Sequential/narrative images |
| `gemini --yolo "/nanobanana prompt"` | Natural language interface |

## Common Options

- `--yolo` - **Required.** Auto-approve all tool actions (no confirmation prompts)
- `--count=N` - Generate N variations (1-8)
- `--preview` - Auto-open generated images
- `--styles="style1,style2"` - Apply artistic styles
- `--format=grid|separate` - Output arrangement

## Common Sizes

| Use Case | Dimensions | Notes |
|----------|------------|-------|
| YouTube thumbnail | 1280x720 | `--aspect=16:9` |
| Blog featured image | 1200x630 | Social preview friendly |
| Square social | 1080x1080 | Instagram, LinkedIn |
| Twitter/X header | 1500x500 | Wide banner |
| Vertical story | 1080x1920 | `--aspect=9:16` |

## Model Selection

Default: `gemini-2.5-flash-image` (~$0.04/image)

For higher quality (4K, better reasoning):

```bash
export NANOBANANA_MODEL=gemini-3-pro-image-preview
```

## Blog Featured Image Examples

```bash
# Modern illustration style
gemini --yolo "/generate 'modern flat illustration of developer coding at laptop, purple and blue gradient background, minimalist style, no text' --preview"

# Professional photography style
gemini --yolo "/generate 'professional editorial photo of coffee cup next to laptop on wooden desk, morning sunlight, shallow depth of field, no text' --count=3"

# Tech/abstract
gemini --yolo "/generate 'abstract visualization of neural network connections, dark background with glowing blue nodes, futuristic style' --preview"
```

## Icon Generation

```bash
gemini --yolo "/icon 'minimalist app logo for productivity tool' --sizes='64,128,256,512' --type='app-icon' --corners='rounded'"
```

## Diagram Generation

```bash
gemini --yolo "/diagram 'user authentication flow with OAuth' --type='flowchart' --style='modern'"
```

## Output Location

All generated images are saved to `./nanobanana-output/` in the current directory.

## Presenting Results

After generation completes:
1. List contents of `./nanobanana-output/` to find generated files
2. Present the most recent image(s) to the user
3. Offer to regenerate with variations if needed

## Refinements and Iterations

When the user asks for changes:
- **"Try again" / "Give me options"**: Regenerate with `--count=3`
- **"Make it more [adjective]"**: Adjust prompt and regenerate
- **"Edit this one"**: Use `gemini --yolo "/edit nanobanana-output/filename.png 'adjustment'"`
- **"Different style"**: Add `--styles="requested_style"` to the command

## Prompt Tips

1. **Be specific**: Include style, mood, colors, composition details
2. **Add "no text"**: If you don't want text rendered in the image
3. **Reference styles**: "editorial photography", "flat illustration", "3D render", "watercolor"
4. **Specify aspect ratio context**: "wide banner", "square thumbnail", "vertical story"

## Troubleshooting

| Problem | Solution |
|---------|----------|
| `GEMINI_API_KEY` not set | `export GEMINI_API_KEY="your-key"` |
| Extension not found | Run install command from setup section |
| Quota exceeded | Wait for reset or switch to flash model |
| Image generation failed | Check prompt for policy violations, simplify request |
| Output directory missing | Will be created automatically on first run |
| Specialty recipe not found | Verify the recipe name against the table above; fall back to generic generation if needed |