Image Generation Skill

Generate images using Nano Banana (Google Gemini Image API). Supports text-to-image and image-to-image generation with configurable options.

Setup

Dependencies

bash

pip install google-genai Pillow

Environment Variable

Set your API key:

bash

export GEMINI_API_KEY="your_api_key_here"

Usage

Basic Text-to-Image

bash

python scripts/generate.py --prompt "A futuristic city at sunset with neon lights" --output city.png

With Aspect Ratio

bash

python scripts/generate.py \
  --prompt "Mountain landscape with a lake" \
  --output landscape.png \
  --aspect-ratio 16:9

Image-to-Image Mode

Use a reference image to guide generation:

bash

python scripts/generate.py \
  --prompt "Make it look like a watercolor painting" \
  --input-image original.png \
  --output watercolor.png

Generate Multiple Images

bash

python scripts/generate.py \
  --prompt "Abstract colorful art" \
  --output art.png \
  --num-images 3

Arguments

Argument	Short	Required	Default	Description
`--prompt`	`-p`	Yes	—	Text prompt describing the desired image
`--output`	`-o`	No	`output.png`	Output path for the generated image
`--model`	`-m`	No	`gemini-2.0-flash-preview-image-generation`	Model to use for generation
`--input-image`	`-i`	No	—	Reference image for image-to-image mode
`--aspect-ratio`	`-a`	No	—	Aspect ratio: `1:1`, `16:9`, `9:16`, `4:3`, `3:4`
`--num-images`	`-n`	No	`1`	Number of images to generate

Available Models

gemini-2.0-flash-preview-image-generation - Fast, optimized for speed and lower latency
imagen-3.0-generate-002 - High quality image generation

Programmatic Usage

Import the function directly in Python:

python

from scripts.generate import generate_image

paths = generate_image(
    prompt="A serene mountain lake under moonlight",
    output_path="./outputs/lake.png",
    aspect_ratio="16:9",
    num_images=2,
)

Tips

Detailed prompts work better: Instead of "a cat", try "a fluffy orange tabby cat sitting on a windowsill, soft morning light, photorealistic"
Specify style: Include style keywords like "digital art", "oil painting", "photorealistic", "anime style"
Use aspect ratios: Match the aspect ratio to your intended use (16:9 for landscapes, 9:16 for portraits/mobile)
Image-to-image: Great for style transfer, variations, or guided modifications of existing images