GIMP utilities for batch image processing

Created by @jontsai | Part of Hacktoolkit

A collection of minimal, Unix-philosophy CLI utilities for automated image processing using GIMP's headless mode and Script-Fu.

Following the Unix philosophy:

• Each tool does one thing well
• Tools use stdin/stdout and can be composed
• Minimal arguments to memorize
• Clear help messages when invoked incorrectly

Clone the repo and add scripts to your PATH, or run directly:

git clone https://github.com/hacktoolkit/gimp-utils.git
cd gimp-utils

Optional: Add to your PATH

export PATH="$PATH:$HOME/code/gimp-utils"

Apply auto white balance (Colors > Auto > White Balance) to images in batch.

Before & After Examples:

Example images courtesy of @SkilletzCafe

Before (Raw)	After (White Balanced)

Usage:

gimp-white-balance INPUT_DIR OUTPUT_DIR [PATTERN]

Arguments:

• INPUT_DIR - Directory containing source images
• OUTPUT_DIR - Directory where processed images will be saved (created if it doesn't exist)
• PATTERN - File pattern to match (default: *.JPG)

Examples:

# Process all JPG files
./gimp-white-balance ./photos ./processed

# Process PNG files
./gimp-white-balance ./photos ./processed "*.png"

# Process with absolute paths
./gimp-white-balance ~/Pictures/unprocessed ~/Pictures/processed

# Process all image types
./gimp-white-balance ./raw ./output "*.{jpg,JPG,png,PNG}"

Output: The script will:

1. Find all matching files in INPUT_DIR
2. Show progress with checkmarks (✓ success, ✗ failure)
3. Save processed images to OUTPUT_DIR with the same filenames

• GIMP 3.0+ installed at /Applications/GIMP.app (macOS)
• Script-Fu support (built into GIMP)
• Bash shell

Platform Support:

• Currently supports macOS only
• Linux/Windows support coming soon (contributions welcome!)

Installation Notes:

• The script expects GIMP to be installed at the standard macOS location: /Applications/GIMP.app
• If GIMP is installed elsewhere, edit the script and update the path on line 69

• GIMP 3.0 Compatibility: These scripts use GIMP 3.0's Script-Fu v3 API
• Non-destructive: Original files are never modified
• Progress indicator: Real-time feedback shows which files succeeded/failed
• Error handling: Continues processing remaining files even if one fails

This tool uses GIMP's batch mode with Script-Fu v3 dialect to process images without GUI overhead. Each image is:

1. Loaded in non-interactive mode
2. Auto white balance applied using gimp-drawable-levels-stretch
3. Flattened to a single layer
4. Saved to the output directory

Contributions are welcome! Please feel free to submit a Pull Request.

Areas for contribution:

• Linux support (detecting GIMP installation paths)
• Windows support
• Additional image processing utilities
• Performance improvements

Created and maintained by @jontsai

Sponsored by @hacktoolkit

MIT License - see LICENSE file for details