nano-banana-imagegen

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Generate and edit images using Google's Nano Banana (Gemini Image API). Use when the user wants to create AI-generated images, edit existing images, create infographics, generate product mockups, design social media graphics, or perform any image generation/manipulation task. Requires GEMINI_API_KEY environment variable.

QUICK START

How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/majiayu000/claude-skill-registry/blob/HEAD/skills/design/nano-banana-imagegen-othreecodes-claude-code-nano-ban/SKILL.md

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Nano Banana Image Generation

Generate and edit images using Google's Gemini Image models (Nano Banana and Nano Banana Pro).

Prerequisites

API Key: Set the GEMINI_API_KEY environment variable
- Get key from: https://aistudio.google.com/apikey
uv: The script uses inline dependencies with uv (no manual install needed)

Quick Start

Using the Script

# Generate an image
uv run scripts/generate_image.py "A futuristic city at sunset" -o city.png

# Edit an existing image
uv run scripts/generate_image.py "Remove the background" -i photo.jpg -o edited.png

# Use Nano Banana Pro for higher quality
uv run scripts/generate_image.py "Create a detailed infographic" -m pro -o infographic.png

Direct Python Usage (with uv)

uv run --with google-genai python -c '
from google import genai
import os

client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])

response = client.models.generate_content(
    model="gemini-2.5-flash-image",
    contents=["Create an image of a cat wearing a space helmet"]
)

for part in response.candidates[0].content.parts:
    if part.inline_data:
        with open("output.png", "wb") as f:
            f.write(part.inline_data.data)
        print("Saved to output.png")
'

Model Selection

Model	Use Case
`gemini-2.5-flash-image` (Nano Banana)	Fast generation, iterations, high volume
`gemini-3-pro-image-preview` (Nano Banana Pro)	Professional quality, text rendering, complex prompts

Common Tasks

Image Generation

uv run scripts/generate_image.py "A serene Japanese garden with cherry blossoms" -o garden.png

Image Editing

uv run scripts/generate_image.py "Change the background to a beach sunset" -i input.jpg -o edited.png

Infographics (use Pro model)

uv run scripts/generate_image.py "Create an infographic about renewable energy" -m pro -o infographic.png

Resources

Script: scripts/generate_image.py - CLI tool with inline uv dependencies
API Reference: See references/api_reference.md for detailed SDK usage
Prompting Guide: See references/prompting_guide.md for effective prompts

Pricing

~$0.039 per image for Nano Banana (1290 tokens per image at $30/1M tokens)