Batch Image Generator

Overview

Batch generate game assets from a structured JSON manifest file. This skill orchestrates multiple image generation skills (text-to-image, generate-image-by-image, background-remover) to produce complete asset sets in one automated run.

When to Use This Skill

Use this skill when:

• Generating multiple game assets at once (characters, UI, backgrounds, effects)
• Need consistent style across all assets
• Want automated variant generation (hover/pressed states, animation frames)
• Require organized output with proper directory structure

Quick Start

Basic Usage

python3 scripts/batch_generate.py manifest.json

With Options

# Dry run (show what would be generated)
python3 scripts/batch_generate.py manifest.json --dry-run

# Skip background removal for all assets
python3 scripts/batch_generate.py manifest.json --skip-remove-bg

# Custom output directory
python3 scripts/batch_generate.py manifest.json --output-dir ./assets

# Resume from a specific asset (skip already generated)
python3 scripts/batch_generate.py manifest.json --resume-from "animal_fox_01"

# Verbose output
python3 scripts/batch_generate.py manifest.json --verbose

Manifest File Format

The manifest is a JSON file defining all assets to generate:

{
  "config": {
    "style": "Q版卡通风格，可爱萌系，大头小身比例2:1，...",
    "default_size": "1024x1024",
    "default_quality": "high",
    "temp_dir": "./temp",
    "skills_dir": ".codebuddy/skills"
  },
  "assets": [
    {
      "id": "animal_panda_01",
      "type": "mother",
      "prompt": "可爱的Q版小熊猫，正面视角，...",
      "output": "images/characters/animal_panda_01.png",
      "size": "1024x1024",
      "quality": "high",
      "remove_bg": true
    },
    {
      "id": "animal_panda_02",
      "type": "variant",
      "mother_id": "animal_panda_01",
      "edit_prompt": "same pose, eyes closed, blinking, peaceful expression",
      "output": "images/characters/animal_panda_02.png",
      "strength": 0.5,
      "remove_bg": true
    },
    {
      "id": "bg_sky",
      "type": "mother",
      "prompt": "梦幻天空背景，淡蓝到白色渐变，...",
      "output": "images/environments/bg_sky.png",
      "size": "1408x640",
      "remove_bg": false
    }
  ]
}

Config Section

Field	Type	Required	Description
style	string	Yes	Global style prompt prepended to all generation prompts
default_size	string	No	Default image size (default: "1024x1024")
default_quality	string	No	Default quality level: low/medium/high (default: "high")
temp_dir	string	No	Temporary directory for intermediate files (default: "./temp")
skills_dir	string	No	Path to skills directory (default: ".codebuddy/skills")

Asset Types

Mother Image (type: "mother")

Base image generated from text prompt.

Field	Type	Required	Description
id	string	Yes	Unique identifier for this asset
type	string	Yes	Must be "mother"
prompt	string	Yes	Text description (style will be prepended)
output	string	Yes	Output file path relative to output_dir
size	string	No	Image size (uses config.default_size if not set)
quality	string	No	Quality level (uses config.default_quality if not set)
remove_bg	boolean	No	Whether to remove background (default: true)
background	string	No	"transparent" or "opaque" (for text-to-image)

Variant Image (type: "variant")

Image generated by editing a mother image.

Field	Type	Required	Description
id	string	Yes	Unique identifier for this asset
type	string	Yes	Must be "variant"
mother_id	string	Yes	ID of the mother image to base this on
edit_prompt	string	Yes	Edit instruction for the variant
output	string	Yes	Output file path relative to output_dir
strength	float	No	Edit strength 0.0-1.0 (default: 0.5)
remove_bg	boolean	No	Whether to remove background (default: true)

Example Manifests

Game Characters with Animation Frames

{
  "config": {
    "style": "Q版卡通风格，可爱萌系，游戏美术资源",
    "default_size": "1024x1024",
    "default_quality": "high"
  },
  "assets": [
    {
      "id": "hero_idle_01",
      "type": "mother",
      "prompt": "勇敢的Q版小骑士，正面站立，手持小剑盾牌，isolated on white",
      "output": "characters/hero_idle_01.png"
    },
    {
      "id": "hero_idle_02",
      "type": "variant",
      "mother_id": "hero_idle_01",
      "edit_prompt": "same character, eyes blinking, slight breath movement",
      "output": "characters/hero_idle_02.png",
      "strength": 0.3
    },
    {
      "id": "hero_walk_01",
      "type": "variant",
      "mother_id": "hero_idle_01",
      "edit_prompt": "same character, left foot forward, walking pose",
      "output": "characters/hero_walk_01.png",
      "strength": 0.5
    }
  ]
}

UI Elements with States

{
  "config": {
    "style": "木质游戏UI，温暖棕色调，圆角设计",
    "default_size": "512x512"
  },
  "assets": [
    {
      "id": "btn_play_normal",
      "type": "mother",
      "prompt": "游戏开始按钮，木质质感，3D立体效果，isolated",
      "output": "ui/btn_play_normal.png"
    },
    {
      "id": "btn_play_hover",
      "type": "variant",
      "mother_id": "btn_play_normal",
      "edit_prompt": "same button, slightly brighter, glow effect",
      "output": "ui/btn_play_hover.png",
      "strength": 0.3
    },
    {
      "id": "btn_play_pressed",
      "type": "variant",
      "mother_id": "btn_play_normal",
      "edit_prompt": "same button, pressed down, darker shadow",
      "output": "ui/btn_play_pressed.png",
      "strength": 0.4
    }
  ]
}

Backgrounds (No BG Removal)

{
  "config": {
    "style": "梦幻插画风格，柔和光影",
    "default_size": "1408x640"
  },
  "assets": [
    {
      "id": "bg_forest",
      "type": "mother",
      "prompt": "神秘森林场景，层叠树木，阳光透过树冠",
      "output": "backgrounds/bg_forest.png",
      "remove_bg": false
    },
    {
      "id": "bg_forest_night",
      "type": "variant",
      "mother_id": "bg_forest",
      "edit_prompt": "same scene, night time, moonlight, fireflies",
      "output": "backgrounds/bg_forest_night.png",
      "strength": 0.6,
      "remove_bg": false
    }
  ]
}

VFX Particles (Black Background)

{
  "config": {
    "style": "game vfx particle, centered",
    "default_size": "512x512"
  },
  "assets": [
    {
      "id": "particle_star",
      "type": "mother",
      "prompt": "golden star particle, bright glow, isolated on solid black background",
      "output": "effects/particle_star.png",
      "remove_bg": false
    },
    {
      "id": "particle_sparkle",
      "type": "mother",
      "prompt": "white sparkle particle, starburst shape, isolated on solid black background",
      "output": "effects/particle_sparkle.png",
      "remove_bg": false
    }
  ]
}

CLI Parameters

Parameter	Short	Description
manifest		Path to JSON manifest file (required)
--output-dir	-o	Base output directory (default: current dir)
--dry-run	-d	Show what would be generated without executing
--skip-remove-bg		Skip background removal for all assets
--resume-from	-r	Resume from specified asset ID (skip previous)
--verbose	-v	Show detailed progress and debug info
--parallel	-p	Number of parallel workers (default: 1, sequential)

Output

The script produces:

1. Generated assets in the specified output paths
2. Temp files in the temp directory (can be cleaned up)
3. Progress log showing completion status
4. Summary report at the end with success/failure counts

Example output:

🎨 Batch Image Generator
========================
📋 Manifest: game_assets.json
📁 Output: ./assets
🎯 Total assets: 15

[1/15] 🖼️  Generating mother: animal_panda_01
       ✅ Generated: images/characters/animal_panda_01.png

[2/15] 🔄 Generating variant: animal_panda_02
       ✅ Generated: images/characters/animal_panda_02.png

...

========================
✅ Completed: 15/15
⏱️  Total time: 12m 34s
📁 Output directory: ./assets

Error Handling

• If a generation fails, the script logs the error and continues with the next asset
• Use --resume-from to restart from a failed asset after fixing issues
• Failed assets are listed in the summary report
• Temp files are preserved for debugging (clean manually if needed)

Best Practices

Manifest Organization

1. Group by category: Put related assets together (all characters, then UI, then backgrounds)
2. Mother before variants: Always define mother images before their variants
3. Consistent naming: Use clear naming convention (e.g., category_name_state.png)

Performance Tips

1. Sequential execution: API doesn't support parallel calls, so assets are generated one by one
2. Resume support: Use --resume-from to continue interrupted batches
3. Dry run first: Use --dry-run to validate manifest before actual generation

Style Consistency

1. Global style in config: Define common style elements in config.style
2. Asset-specific details: Put unique details in each asset's prompt
3. Variant consistency: Use similar strength values for related variants

Dependencies

This skill requires the following skills to be available:

• text-to-image - For generating mother images
• generate-image-by-image - For generating variants
• background-remover - For removing backgrounds

Install Python dependencies:

pip install requests Pillow rembg

Files in This Skill

• SKILL.md - This documentation
• scripts/batch_generate.py - Main batch generation script