gemini-imagegen

Gemini Image Generation (Nano Banana 2)

Generate and edit images using Google's Gemini API.

Before You Start

1. Check if GEMINI_API_KEY is set in the environment. If not present, ask the user to configure it:

   • Get a Gemini API key from https://aistudio.google.com/apikey
   • In Claude Desktop, click the gear icon next to the "Local" dropdown
   • Add GEMINI_API_KEY=your_key_here in the Environment variables dialog
   • Click "Save changes"

2. Use the venv Python for all script invocations. The scripts require Python 3.10+ with google-genai and Pillow:

SCRIPTS_DIR="${CLAUDE_PLUGIN_ROOT}/skills/gemini-imagegen/scripts"
PYTHON="${SCRIPTS_DIR}/.venv/bin/python3"

If the venv doesn't exist yet, create it:

python3.12 -m venv "${SCRIPTS_DIR}/.venv"
"${SCRIPTS_DIR}/.venv/bin/pip" install google-genai Pillow

Scripts

Use these scripts for all image generation tasks. Always invoke with $PYTHON (the venv python from above):

generate_image.py - Create images from text

Use when: User wants to create a new image from a text description

$PYTHON "${SCRIPTS_DIR}/generate_image.py" "prompt" output.png [--model MODEL] [--aspect RATIO] [--size SIZE]

edit_image.py - Modify existing images

Use when: User wants to edit or transform an existing image

$PYTHON "${SCRIPTS_DIR}/edit_image.py" input.png "instruction" output.png [--model MODEL] [--aspect RATIO] [--size SIZE]

compose_images.py - Combine multiple images

Use when: User wants to merge elements from multiple images (up to 14)

$PYTHON "${SCRIPTS_DIR}/compose_images.py" "instruction" output.png image1.png [image2.png ...] [--model MODEL] [--aspect RATIO] [--size SIZE]

multi_turn_chat.py - Iterative refinement

Use when: User wants to refine an image through multiple rounds of feedback

$PYTHON "${SCRIPTS_DIR}/multi_turn_chat.py" [--model MODEL] [--output-dir DIR]

Script Options

Option	Values
--model	gemini-3.1-flash-image-preview (default, fastest, best instruction following), gemini-3-pro-image-preview (fallback / best quality, text rendering, 4K), gemini-2.5-flash-image (stable/GA, legacy)

Model selection: Try gemini-3.1-flash-image-preview first (fastest, great quality). If it fails or the result is unsatisfactory (e.g., poor text rendering, complex composition), fall back to gemini-3-pro-image-preview which produces studio-quality output at the cost of speed. | --aspect | 1:1, 1:4, 1:8, 2:3, 3:2, 3:4, 4:1, 4:3, 4:5, 5:4, 8:1, 9:16, 16:9, 21:9 | | --size | 512 (3.1 flash only), 1K, 2K, 4K (pro only) |

remove_bg.py - Remove image backgrounds

Use when: User wants to remove the background from an image (uses macOS Shortcuts)

$PYTHON "${SCRIPTS_DIR}/remove_bg.py" input.jpg [output.png]

If no output path is given, saves to input_nobg.png in the same folder. Requires a one-time setup of a macOS Shortcut named "Remove Background" — the script will print setup instructions if the shortcut is missing.

Prompting Tips

Write prompts like Midjourney experts - be detailed and specific:

• Photorealistic: Include camera details (lens, lighting, angle, mood)

  "A photorealistic close-up portrait, 85mm lens, soft golden hour light, shallow depth of field"

• Stylized art: Specify style, outlines, shading explicitly

  "A kawaii-style sticker of a happy red panda, bold outlines, cel-shading, white background"

• Text in images: Use pro model, be explicit about font and placement

  "Logo with text 'Daily Grind' in clean sans-serif, black and white, coffee bean motif"

• Product mockups: Describe lighting setup and surface

  "Studio-lit product photo on polished concrete, three-point softbox setup, 45-degree angle"