Nano-Banana Image Generation

VerifiedSafe

Generates images using Google's Nano-Banana (Gemini 2.5 Flash Image) model. Automatically enhances user prompts for better results. Supports resolutions from 1K to 4K, various aspect ratios, and flash/pro model options. Use when the user asks to create or generate an image.

Sby Skills Guide Bot
ContentIntermediate
706/2/2026
Claude Code
#image-generation#gemini#ai-art#prompt-engineering

Recommended for

Our review

Generates images using Google's Nano-Banana (Gemini 2.5 Flash) model, automatically enhancing user prompts for better results.

Strengths

  • Automatic prompt enhancement for improved image quality
  • Supports multiple resolutions (1K, 2K, 4K) and aspect ratios
  • Runs in background with macOS notification and auto-open

Limitations

  • Requires a valid Gemini API key set up locally
  • Limited to Gemini 2.5 Flash model (no other engines)
When to use it

Use this skill when the user requests generating an image, illustration, or any visual content.

When not to use it

Do not use if an actual image needs to be edited or if the user asks for video or animation.

Security analysis

Safe
Quality score90/100

The skill only invokes a dedicated shell script for image generation with user-provided prompts. No destructive commands, network exfiltration, or obfuscated payloads are present. The troubleshooting section suggests manual keychain access, but the skill does not execute that automatically, so risk is minimal.

No concerns found

Examples

Basic image generation
Generate a cat
High-resolution landscape
Create a 4K image of mountains
Widescreen wallpaper with save location
Generate a sunset, save to desktop

name: nano-banana description: Generate images using Google's Nano-Banana (Gemini 2.5 Flash Image) model. Use when the user asks to generate, create, or make an image, picture, or illustration. allowed-tools: Read, Bash

Nano-Banana Image Generation

Generate images using Google's Gemini Image models.

IMPORTANT: Enhance User Prompts

Before generating, always enhance the user's prompt using the techniques in PROMPTING.md.

Quick Enhancement Formula

[Subject] + [Style] + [Lighting] + [Composition] + [Quality]

Example Enhancement

  • User says: "a cat"
  • Enhanced: "A fluffy orange tabby cat with bright green eyes, photorealistic, soft natural window lighting, shallow depth of field, rule of thirds composition"

For detailed prompting techniques, templates, and style keywords, see PROMPTING.md.

Quick Start

~/.claude/skills/nano-banana/scripts/generate.sh "your prompt here"

Options

| Option | Description | Default | |--------|-------------|---------| | --output PATH | Save to specific file | ~/Pictures/nano-banana/<timestamp>.png | | --size SIZE | Resolution: 1K, 2K, 4K | 1K | | --aspect RATIO | Aspect ratio | 1:1 | | --flash | Use Flash model (faster, lower quality) | Pro |

Aspect Ratios

1:1, 16:9, 9:16, 4:3, 3:4, 3:2, 2:3

Resolutions

  • 1K - Standard (default, fast)
  • 2K - High resolution (requires Pro model)
  • 4K - Maximum resolution (requires Pro model)

Interpreting User Requests

Parse the user's request and map to script options:

| User says | Script call | |-----------|-------------| | "Generate a cat" | generate.sh "a cat" | | "Create a 4K image of mountains" | generate.sh "mountains" --size 4K | | "Make a landscape wallpaper" | generate.sh "landscape" --aspect 16:9 | | "High quality portrait of a robot" | generate.sh "portrait of a robot" --pro --aspect 3:4 | | "Generate a sunset, save to desktop" | generate.sh "a sunset" --output ~/Desktop/sunset.png | | "4K widescreen cyberpunk city" | generate.sh "cyberpunk city" --size 4K --aspect 16:9 |

Keywords to watch for:

  • Resolution: "4K", "high res", "high resolution", "2K", "large" → use --size
  • Quality: "high quality", "detailed", "professional" → use --pro
  • Orientation: "landscape", "widescreen", "wallpaper" → --aspect 16:9
  • Orientation: "portrait", "vertical", "phone wallpaper" → --aspect 9:16
  • Save location: "save to", "put it in", "output to" → --output

Behavior

  • Runs in background (won't block Claude)
  • Sends macOS notification when complete
  • Auto-opens the image when done
  • Images saved to ~/Pictures/nano-banana/ by default

Troubleshooting

Check the error log:

cat ~/.claude/skills/nano-banana/last-error.log

Verify API key:

security find-generic-password -a "$USER" -s "GEMINI_API_KEY" -w | head -c 10
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