nano-banana

• API key set as GOOGLE_API_KEY or GEMINI_API_KEY environment variable
• The scripts include a bundled virtual environment (.venv/) with google-genai pre-installed
• Scripts can be called directly: ~/.claude/skills/nano-banana/scripts/generate_image.py

| Model | ID | Best For |

|-------|----|----------|

| Flash | gemini-2.5-flash-image | Fast generation, high volume, low latency |

| Pro | gemini-3-pro-image-preview | Professional quality, 4K, advanced reasoning |

| Capability | Script | Description |

|------------|--------|-------------|

| Image Generation | generate_image.py | Create images from text prompts |

| Image Editing | edit_image.py | Modify existing images with instructions |

| Batch Generation | batch_generate.py | Generate multiple images in parallel |

| Multi-turn Editing | chat_session.py | Iterative refinement via conversation |

Generate a Single Image

```bash

python scripts/generate_image.py "a sunset over mountains" sunset.png

```

With options:

```bash

python scripts/generate_image.py "modern office" office.png --model pro --aspect 16:9 --size 4K

```

Edit an Existing Image

```bash

python scripts/edit_image.py photo.png "remove the background" result.png

```

Batch Generation

Create a prompts file (prompts.json):

```json

[

{"prompt": "slide 1: intro graphic", "filename": "slide_01.png", "aspect": "16:9"},

{"prompt": "slide 2: data visualization", "filename": "slide_02.png", "aspect": "16:9"}

]

```

Generate all:

```bash

python scripts/batch_generate.py prompts.json ./output/ --parallel 3

```

Or use a simple text file (one prompt per line):

```bash

python scripts/batch_generate.py prompts.txt ./output/ --aspect 16:9

```

Multi-turn Editing Session

Start an interactive session:

```bash

python scripts/chat_session.py --output-dir ./images/

```

Resume a previous session:

```bash

python scripts/chat_session.py --session-file session.json

```

Send a single refinement:

```bash

python scripts/chat_session.py --session-file session.json --message "make it more vibrant"

```

generate_image.py

Generate a single image from a text prompt.

```

Usage: python scripts/generate_image.py "prompt" output.png [options]

Options:

--model, -m Model: flash (default) or pro

--aspect, -a Aspect ratio: 1:1 (default), 16:9, 9:16, 21:9, 4:3, 3:4

--size, -s Resolution (pro only): 1K, 2K, 4K

```

edit_image.py

Edit an existing image using text instructions.

```

Usage: python scripts/edit_image.py input.png "instructions" output.png [options]

Options:

--model, -m Model: flash (default) or pro

```

batch_generate.py

Generate multiple images from a prompts file.

```

Usage: python scripts/batch_generate.py prompts.json output_dir/ [options]

Options:

--model, -m Model: flash (default) or pro

--aspect, -a Default aspect ratio: 1:1 (default)

--parallel, -p Number of parallel workers: 1 (default)

--json Output results as JSON

```

chat_session.py

Multi-turn image generation/editing session.

```

Usage: python scripts/chat_session.py [options]

Options:

--model, -m Model: flash (default) or pro

--session-file, -s Path to session state file (JSON)

--output-dir, -o Directory for output images: . (default)

--initial, -i Initial prompt to start with

--message Send single message (non-interactive)

```

Prompting Tips

1. Be specific: "A red sports car on a mountain road at sunset" works better than "a car".
2. Describe style: Include art style, mood, lighting, and camera angle.
3. Use negative space: Describe what should NOT be in the image when needed.

Editing Tips

1. Target specific elements: "Change only the sky to purple" is better than "make it purple".
2. Reference the original: "Keep the composition but change the color scheme".
3. Iterative refinement: Use multi-turn sessions for complex edits.

Performance

• Use flash model for quick iterations and high volume.
• Use pro model for final production assets and 4K output.
• Use batch generation with --parallel for multiple images.

For detailed API documentation, see [references/gemini-api.md](references/gemini-api.md).

For prompting techniques, see [references/prompt-guide.md](references/prompt-guide.md).

For common editing patterns, see [references/editing-patterns.md](references/editing-patterns.md).