nano-banana-image-generator

name	nano-banana-image-generator
description	Generate images using Google's Nano Banana 2 (Gemini 3.1 Flash Image Preview). Use when creating infographics, diagrams, thumbnails, social media graphics, or any AI-generated images. Costs $0.067/image.
allowed-tools	Bash, Read, Write
category	visual-communication
requires	{"env":["GEMINI_API_KEY","GOOGLE_API_KEY"],"binaries":["python3"]}
metadata	{"version":"1.0","changelog":["1.0: Promoted to trinity-skills library (2026-08-04)"]}

Nano Banana Image Generator

Generate images using Google's Gemini 3.1 Flash Image Preview model (codename: Nano Banana 2).

Quick Start

Generate a simple image:

bash ~/.claude/skills/nano-banana-image-generator/scripts/generate.sh "A red apple on white background" apple.png

Generate a 16:9 thumbnail:

python3 ~/.claude/skills/nano-banana-image-generator/scripts/generate_thumbnail.py "YouTube thumbnail showing AI agents" /tmp/thumb.png

Generate with custom output directory:

OUTPUT_DIR=/tmp bash ~/.claude/skills/nano-banana-image-generator/scripts/generate.sh "Sunset over mountains" sunset.png

Scripts

Script	Purpose	Output
scripts/generate.sh	General image generation	1024x1024 PNG
scripts/generate_thumbnail.py	16:9 thumbnails	1344x768 PNG
scripts/generate_image.py	Python with aspect ratio control	Configurable

Pricing & Limits

• Cost: $0.067 per image
• Free tier: 500 requests/day
• Generation time: ~22 seconds
• Resolution: 1024x1024 (square), 1344x768 (16:9)

Best Practices

For detailed prompt engineering and brand styling guidelines, see best_practices.md.

Critical Constraints

Element	Maximum
Visual boxes/shapes	10 maximum
Text pieces/labels	10 maximum
Hierarchy levels	3 maximum

Prompt Structure

DO: Write narrative descriptions

Create a simple infographic with black background showing a central concept
with 4-5 supporting elements. Use white text, DM Sans font, bold titles.

DON'T: Use keyword lists

LinkedIn post, gradient, red, white, large text, 15 boxes, arrows everywhere

Brand Styling (Eugene's)

Include in prompts for brand consistency:

Use Eugene's brand style: black background (#000000), white text (#ffffff),
DM Sans font, bold 700 weight for titles, clean minimal design.

Use Cases

Perfect For:

• Social media infographics and carousels
• YouTube thumbnails
• Diagrams and technical documentation
• Product mockups
• Mobile-optimized content

Not Ideal For:

• Hyper-realistic photography
• Complex multi-font typography
• Fine detail technical renders

Environment Variables

• GOOGLE_API_KEY or GEMINI_API_KEY - API key (required)
• OUTPUT_DIR - Output directory (default: current directory)

Examples

Infographic:

bash scripts/generate.sh "Simple framework diagram with black background. CENTER: 'AI Agents' in large white text. SURROUNDING: 4 icons for Planning, Memory, Tools, Learning. DM Sans font, minimal design." agents_framework.png

Thumbnail:

python3 scripts/generate_thumbnail.py "Professional YouTube thumbnail: bold white text 'DEEP AGENTS' on dramatic black background with subtle blue glow, tech aesthetic" deep_agents_thumb.png