Nano Image Generator

Generate images using Nano Banana Pro (Gemini 3 Pro Preview) for any visual asset needs. Supports reference images for style transfer and character consistency.

Quick Start

Basic generation

python scripts/generate_image.py "A friendly robot mascot waving" --output ./mascot.png

With style reference (keep same visual style)

python scripts/generate_image.py "Same style, new content" --ref ./reference.jpg --output ./new.png

Script Usage python scripts/generate_image.py --output [options]

Required:

prompt - Image description --output, -o - Output file path

Options:

--aspect, -a - Aspect ratio (default: 1:1) Square: 1:1 Portrait: 2:3, 3:4, 4:5, 9:16 Landscape: 3:2, 4:3, 5:4, 16:9, 21:9 --size, -s - Resolution: 1K, 2K (default), 4K --ref, -r - Reference image (can use multiple times, max 14) Reference Images

Gemini supports up to 14 reference images for:

Style Transfer

Keep the visual style (colors, textures, mood) from a reference:

python scripts/generate_image.py "New scene with mountains, same visual style as reference" \ --ref ./style-reference.jpg --output ./styled-mountains.png

Character Consistency

Maintain character appearance across multiple images:

python scripts/generate_image.py "Same character now in a forest setting" \ --ref ./character.png --output ./character-forest.png

Multi-Image Fusion

Combine elements from multiple references:

python scripts/generate_image.py "Combine the style of first image with subject of second" \ --ref ./style.png --ref ./subject.png --output ./combined.png

Serial Image Generation (Batch Workflow)

For generating a series with consistent style:

Generate first image Use first image as --ref for subsequent images Each new image inherits the established style

Generate cover

python scripts/generate_image.py "Tech knowledge card cover" -o ./01-cover.png

Generate subsequent cards with style reference

python scripts/generate_image.py "Card 2 content, same style" --ref ./01-cover.png -o ./02-card.png python scripts/generate_image.py "Card 3 content, same style" --ref ./01-cover.png -o ./03-card.png

Workflow

Determine output location - Place images where contextually appropriate:

App icons → ./assets/icons/ Marketing → ./marketing/ UI elements → ./src/assets/ General → ./generated/

Craft effective prompts - Be specific and descriptive:

Include style: "flat design", "3D rendered", "watercolor", "minimalist" Include context: "for a mobile app", "website hero image" Include details: colors, mood, composition For references: mention "same style as reference" or "keep the visual style"

Choose appropriate settings:

Icons/logos → --aspect 1:1 Banners/headers → --aspect 16:9 or 21:9 Mobile screens → --aspect 9:16 Xiaohongshu cards → --aspect 3:4 Photos → --aspect 3:2 or 4:3 Examples

App icon:

python scripts/generate_image.py "Minimalist flat design app icon of a lightning bolt, purple gradient background, modern iOS style" \ --output ./assets/app-icon.png --aspect 1:1

Marketing banner:

python scripts/generate_image.py "Professional website hero banner for a productivity app, abstract geometric shapes, blue and white color scheme" \ --output ./public/images/hero-banner.png --aspect 16:9

Xiaohongshu knowledge card:

python scripts/generate_image.py "Tech knowledge card, dark blue purple gradient, neon cyan accents, code block style, Chinese text '标题'" \ --output ./xiaohongshu/card.png --aspect 3:4

Style transfer:

python scripts/generate_image.py "Transform this photo into watercolor painting style" \ --ref ./photo.jpg --output ./watercolor.png

Character in new scene:

python scripts/generate_image.py "Same character from reference, now sitting in a cafe, warm lighting" \ --ref ./character.png --output ./character-cafe.png --aspect 3:2

Prompt Tips Be specific - "A red apple on a wooden table" vs "an apple" Include style - "in the style of pixel art" or "photorealistic" Mention purpose - "for a children's book" affects the output style Describe composition - "centered", "rule of thirds", "close-up" Specify colors - Explicit color palettes yield better results Reference prompts - Use "same style as reference", "keep the visual aesthetic", "match the color palette" Avoid - Don't ask for complex text in images (use overlays instead) Limitations Maximum 14 reference images per request Text rendering may be imperfect (better to overlay text separately) Very specific brand logos may not reproduce exactly