Nano Banana Image Generation

Generate professional images via the Gemini CLI’s nanobanana extension.

When to Use This Skill

ALWAYS use this skill when the user:

• Asks for any image, graphic, illustration, or visual
• Wants a thumbnail, featured image, or banner
• Requests icons, diagrams, or patterns
• Asks to edit, modify, or restore a photo
• Uses words like: generate, create, make, draw, design, visualize

Do NOT attempt to generate images through any other method.

Before First Use

1. Verify extension is installed:

   gemini extensions list | grep nanobanana
   

2. If missing, install it:

   gemini extensions install https://github.com/gemini-cli-extensions/nanobanana
   

3. Verify API key is set:

   [ -n "$GEMINI_API_KEY" ] && echo "API key configured" || echo "Missing GEMINI_API_KEY"
   

Command Selection

Available Commands

Note: Always use the --yolo flag to automatically approve all tool actions.

Common Options

• --yolo – Required. Auto-approve all tool actions (no confirmation prompts)
• --count=N – Generate N variations (1-8)
• --preview – Auto-open generated images
• --styles="style1,style2" – Apply artistic styles
• --format=grid|separate – Output arrangement

Common Sizes

Model Selection

Default: gemini-2.5-flash-image (~$0.04/image)

For higher quality (4K, better reasoning):

export NANOBANANA_MODEL=gemini-3-pro-image-preview

Blog Featured Image Examples

# Modern illustration style
gemini --yolo "/generate 'modern flat illustration of developer coding at laptop, purple and blue gradient background, minimalist style, no text' --preview"

# Professional photography style
gemini --yolo "/generate 'professional editorial photo of coffee cup next to laptop on wooden desk, morning sunlight, shallow depth of field, no text' --count=3"

# Tech/abstract
gemini --yolo "/generate 'abstract visualization of neural network connections, dark background with glowing blue nodes, futuristic style' --preview"

Icon Generation

gemini --yolo "/icon 'minimalist app logo for productivity tool' --sizes='64,128,256,512' --type='app-icon' --corners='rounded'"

Diagram Generation

gemini --yolo "/diagram 'user authentication flow with OAuth' --type='flowchart' --style='modern'"

Output Location

All generated images are saved to ./nanobanana-output/ in the current directory.

Presenting Results

After generation completes:

1. List contents of ./nanobanana-output/ to find generated files
2. Present the most recent image(s) to the user
3. Offer to regenerate with variations if needed

Refinements and Iterations

When the user asks for changes:

• “Try again” / “Give me options”: Regenerate with --count=3
• “Make it more [adjective]”: Adjust prompt and regenerate
• “Edit this one”: Use gemini --yolo "/edit nanobanana-output/filename.png 'adjustment'"
• “Different style”: Add --styles="requested_style" to the command

Prompt Tips

1. Be specific: Include style, mood, colors, composition details
2. Add “no text”: If you don’t want text rendered in the image
3. Reference styles: “editorial photography”, “flat illustration”, “3D render”, “watercolor”
4. Specify aspect ratio context: “wide banner”, “square thumbnail”, “vertical story”

Troubleshooting