Nano Banana
Generate images using Google Generative AI API. Supports any image type: illustrations, realistic photos, product mockups, logos, scenes, patterns, UI concepts, and more.
Setup (first time only)
If GOOGLE_AI_API_KEY is not set:
- Go to https://aistudio.google.com/apikey
- Click "Create API Key" (free, no credit card needed)
- Add to shell profile:
echo 'export GOOGLE_AI_API_KEY="your-key-here"' >> ~/.zshrc source ~/.zshrc
Interactive Workflow
- Ask for concept - What image do you want to create?
- Ask for type - Illustration, photo, mockup, logo, etc.
- Ask for quality level - nano-banana-2 (fast, good quality) or nano-banana-pro (best quality, slower)?
- Ask for size - What dimensions/aspect ratio?
- Ask for style - User describes their aesthetic, colors, or picks a preset
- Build prompt - Combine type + style + concept + size into a generation prompt
- Generate - Run
scripts/generate.py - Preview - Open in default viewer
Models & Cost
Present these options and confirm cost before generating:
| Model | Flag | Cost/image | Best for |
|---|---|---|---|
| Nano Banana 2 (default) | -m nano-banana-2 | ~$0.04 | Latest, fastest, good quality |
| Nano Banana Pro | -m nano-banana-pro | ~$0.06 | Best quality, slower |
| Nano Banana (legacy) | -m nano-banana | ~$0.04 | Original model |
Always confirm: "This will cost approximately $X.XX. Proceed?"
Sizes
Ask user what size they need. Add the size instruction to the END of the prompt:
| Size | Use case | Prompt suffix |
|---|---|---|
| Square (1:1) | Blog posts, social | Square 1:1 aspect ratio. |
| Wide (16:9) | Headers, banners, YouTube | Wide format 16:9 aspect ratio. |
| Portrait (9:16) | Stories, mobile | Portrait 9:16 aspect ratio. |
| Landscape (3:2) | Photos, cards | Landscape 3:2 aspect ratio. |
Building the Prompt
If user has brand/style preferences
Ask: "Do you have specific colors, aesthetic, or brand style you'd like?"
Use their answer to build the prompt with this structure:
[IMAGE TYPE], [AESTHETIC/STYLE], [COLOR PALETTE].
[CONCEPT DESCRIPTION]
[STYLE CONSTRAINTS]. [ASPECT RATIO]Image Type Presets
Illustrations
Watercolor - Soft, whimsical, hand-drawn
Whimsical hand-drawn watercolor illustration, soft [USER_COLOR] palette with warm accents.
Simple composition with ONE/TWO main elements:
[CONCEPT]
Style: Simple and clean like Notion illustrations. NOT complex. NOT busy.
NO text. Cream background. Square 1:1.Monochromatic - Single color, clean lines
MONOCHROMATIC [USER_COLOR] illustration - use ONLY shades of [USER_HEX] throughout. Ultra high quality.
[CONCEPT]
Style: Clean lines, modern like Notion/Slack. NO other colors.Flat/Editorial - Detailed, informative
Detailed flat illustration in [USER_COLOR] palette, editorial quality.
[CONCEPT]
Style: Clean linework. Modern editorial feel. High detail.
Wide format 16:9.Minimal line art - Simple outlines, one accent
Minimal line art, thin black outlines with [USER_COLOR] as single accent color.
[CONCEPT]
Style: Minimal, lots of whitespace. NO fills except accent. White background.Photos / Realistic
Product photo - Clean, studio-style
Professional product photography, studio lighting, clean [white/colored] background.
[PRODUCT DESCRIPTION]
Ultra high quality, sharp focus, soft shadows. [ASPECT RATIO]Lifestyle photo - Natural, contextual
Lifestyle photography, natural lighting, [warm/cool] tones.
[SCENE DESCRIPTION]
Authentic feel, shallow depth of field. [ASPECT RATIO]Scene / Environment - Places, spaces
[Photorealistic/Cinematic] scene, [LIGHTING DESCRIPTION], [MOOD].
[SCENE DESCRIPTION]
High detail, professional photography quality. [ASPECT RATIO]Design & Branding
Logo concept - Clean, symbolic
Minimalist logo design on white background. Clean vector style.
[BRAND/CONCEPT DESCRIPTION]
Simple, memorable, works at small sizes. NO text. Square 1:1.UI mockup - Interface concepts
Clean UI design mockup, modern interface, [light/dark] theme.
[SCREEN/COMPONENT DESCRIPTION]
Style: Modern SaaS aesthetic, clean typography, subtle shadows. [ASPECT RATIO]Pattern / Texture - Repeating visuals
Seamless [PATTERN TYPE] pattern, [USER_COLOR] palette.
[PATTERN DESCRIPTION]
Tileable, consistent spacing, high quality. Square 1:1.Generation
Single image
python3 scripts/generate.py "<full_prompt>" -o ~/Desktop/<filename>.png -m <model> --open-mselects the model (default:nano-banana-2)--openopens the image in the default viewer after generation- Use descriptive kebab-case filenames (e.g.,
laptop-notifications.png) - If user doesn't like the result, tweak the prompt and regenerate
Batch generation (same style)
When user needs multiple images in a consistent style (e.g., blog series, icon set, product shots):
- Define the style prompt once (colors, aesthetic, constraints)
- Ask user for a list of concepts/subjects
- Generate each image reusing the same style prefix, only changing the concept
- Save all to the same folder with numbered or descriptive names
Example batch flow:
# Same style, different concepts
python3 scripts/generate.py "<STYLE PREFIX> A laptop with sparkles. <STYLE SUFFIX>" -o ~/Desktop/batch/01-laptop.png -m nano-banana-2
python3 scripts/generate.py "<STYLE PREFIX> A rocket launching. <STYLE SUFFIX>" -o ~/Desktop/batch/02-rocket.png -m nano-banana-2
python3 scripts/generate.py "<STYLE PREFIX> A lightbulb moment. <STYLE SUFFIX>" -o ~/Desktop/batch/03-lightbulb.png -m nano-banana-2Confirm total cost before starting: "This batch of N images will cost approximately $X.XX total. Proceed?"
Tips for Better Results
- Keep concepts focused: describe the main subject clearly
- Specify what you DON'T want (no text, no watermarks, no blurry elements)
- Include aspect ratio (1:1 for social, 16:9 for headers, 9:16 for stories)
- Add "Ultra high quality" or "High detail" for sharper output
- For illustrations: reference styles (Notion, Slack, Linear, Dribbble)
- For photos: describe lighting, angle, and mood
- For logos/design: emphasize simplicity and scalability
- If result isn't right, iterate: adjust the prompt and regenerate