Gemini Image Generation

Generate images with support for multiple reference images (up to 14).

Setup

Required: GEMINI_API_KEY environment variable

Get your API key at: https://aistudio.google.com/apikey

Set it:

export GEMINI_API_KEY="your-key-here"

Or in your OpenClaw config (~/.openclaw/openclaw.json):

{
  "skills": {
    "entries": {
      "gemini-image": {
        "env": { "GEMINI_API_KEY": "your-key-here" }
      }
    }
  }
}

Usage

# Generate from prompt
uv run {baseDir}/scripts/generate.py -p "a sunset over mountains" -o sunset.png

# Edit/transform one image
uv run {baseDir}/scripts/generate.py -p "make this pop art style" -i photo.png -o popart.png

# Combine multiple references (up to 14)
uv run {baseDir}/scripts/generate.py -p "combine style of first with content of second" \
  -i style-ref.png -i content.png -o combined.png

# With aspect ratio
uv run {baseDir}/scripts/generate.py -p "wide landscape" -a "16:9" -o wide.png

# Higher resolution
uv run {baseDir}/scripts/generate.py -p "detailed portrait" -r 2K -o portrait.png

Options

Models

• pro (gemini-3-pro-image-preview) — Highest quality, thinking mode, up to 14 refs, aspect ratio + resolution
• flash2 (gemini-3.1-flash-image-preview) — NEW: Nano Banana 2. Best price/perf, thinking levels, great text rendering, localization, aspect ratio + resolution + 512px
• flash (gemini-2.5-flash-image) — Older Flash, simpler config, no aspect ratio/resolution control
• exp (gemini-2.0-flash-exp) — Experimental, good for edits

When to use flash2 vs pro:

• flash2 — Fast iterations, text-heavy images, localization, bulk generation, great quality at lower cost
• pro — Maximum quality, complex multi-reference compositions, highest fidelity

Aspect Ratios (pro/flash2)

1:1 · 2:3 · 3:2 · 3:4 · 4:3 · 4:5 · 5:4 · 9:16 · 16:9 · 21:9 · 4:1 · 1:4 · 8:1 · 1:8

Thinking Levels (pro/flash2)

Control how much the model reasons before generating:

• minimal (default) — Fast, good for simple prompts
• high — Better quality for complex multi-element prompts
• dynamic — Model decides how much thinking is needed

# Complex scene with high thinking
uv run {baseDir}/scripts/generate.py -p "detailed city scene with specific text overlay" -m flash2 -t high -o city.png

Reference Image Limits

Batch Generation (50% cheaper)

For bulk jobs that can wait 24hr, use the batch API.

"Batch Submit" Workflow

When user says "batch submit", follow this automated workflow:

1. Submit batch job — Create JSONL, run batch.py submit
2. Create hourly cron — Check batch status every hour
3. On completion — Download images to specified output directory
4. Deliver to originating channel — Send all images to the channel where the request was made (Telegram, Discord, Signal, etc.)
5. Self-disable cron — Remove the cron job after successful delivery

Cron job text template:

Check gemini-image batch [BATCH_ID]. If complete: download to [OUTPUT_DIR], send all images to [CHANNEL], then disable this cron job.

Manual Batch Commands

1. Create requests JSONL (one per line):

{"key": "sunset", "prompt": "a sunset over mountains", "aspect_ratio": "16:9", "resolution": "2K"}
{"key": "portrait", "prompt": "corporate headshot", "input_images": ["/path/to/ref.png"]}

2. Submit batch:

uv run {baseDir}/scripts/batch.py submit requests.jsonl

3. Check status (typically ready within 24hr):

uv run {baseDir}/scripts/batch.py status

4. Download when done:

uv run {baseDir}/scripts/batch.py download -o ./images/

When to use batch vs instant:

• Need it now → generate.py (instant, full price)
• Bulk generation, can wait → batch.py (24hr, 50% off)

Prompting Guide

See references/prompting.md for detailed strategies:

Generation:

• Photorealistic scenes (camera/lens/lighting terms)
• Stylized illustrations & stickers (transparent backgrounds)
• Text rendering (logos, typography)
• Product mockups (commercial photography)
• Minimalist/negative space design
• Sequential art (comics, storyboards)
• Google Search grounding (real-time info)
• iOS wireframes & UI mockups

Editing:

• Adding/removing elements
• Inpainting (semantic masking)
• Style transfer
• Combining multiple images
• High-fidelity detail preservation
• Sketch → finished image
• Character consistency (360 views)

Core principle: Describe the scene narratively, don't just list keywords.

Tips

• Images go first in context, prompt last — order -i flags intentionally
• For style transfer: first image = style reference, second = content
• Pro model uses "Thinking" phase to plan composition before generating
• Timestamps in filenames: 2026-01-26-sunset.png
• Script outputs MEDIA: line for Clawdbot auto-attach

Draft Mode (Preview Before Generate)

For complex generations — especially UI mockups and wireframes — use a two-step workflow:

Step 1: Draft the JSON Prompt

When user asks for a wireframe or complex image, show the structured prompt first instead of generating immediately:

Here's the prompt I'll use:

{
  "image_type": "UI mockup",
  "device": {"frame": "iPhone 16 Pro", "orientation": "portrait"},
  "design_system": {
    "style": "iOS 18 native",
    "corners": "rounded, 16px radius",
    "shadows": "soft drop shadows",
    "spacing": "8pt grid",
    "font": "SF Pro"
  },
  "layout": {
    "header": "Navigation bar with back button and title 'Settings'",
    "content": "List of settings items with icons and toggles",
    "bottom": "Tab bar with 4 items"
  }
}

Want me to generate this, or should I adjust anything first?

Step 2: User Approves or Tweaks

• "looks good" / "generate" → Run the generation
• "make the header bigger" / "add a search bar" → Update JSON, show again
• "use flash model" → Note the model preference

Step 3: Generate

Convert JSON to narrative prompt and run:

uv run {baseDir}/scripts/generate.py \
  -p "[narrative version of JSON]" \
  -o mockup.png \
  -a "9:16" \
  -m pro

When to Use Draft Mode

Trigger phrases for draft mode:

• "wireframe", "mockup", "UI", "screen design"
• "let me review the prompt"
• "show me what you'll generate"
• "draft first"

Edit iterations:

• Simple tweaks (color change, font swap) → Generate directly, no approval needed
• Structural changes (new elements, layout changes, removing sections) → Show change summary for approval

iOS Wireframes

Quick example:

uv run {baseDir}/scripts/generate.py \
  -p "Convert this wireframe to high-fidelity iOS 18 UI. iPhone 16 Pro frame, rounded corners, soft shadows, SF Pro font. Interpret: scribbles→images, rectangles→buttons, lines→text" \
  -i wireframe-sketch.png \
  -o mockup.png \
  -a "9:16"

See references/prompting.md for detailed templates including JSON-structured prompts and multi-screen flows.