Image Optimization Script

A powerful bash script for optimizing images to reduce file size while maintaining quality. Perfect for web development projects, git repositories, and general image processing workflows.

Features

• Smart Resizing: Automatically resizes images larger than specified dimensions while maintaining aspect ratio
• Quality Optimization: Compresses images to specified JPEG quality (default: 85%)
• Metadata Handling: Strips EXIF, GPS, and other metadata by default (configurable)
• Git Integration: Can process only staged images in git repositories
• Interactive Mode: Ask for confirmation before processing each image
• Batch Processing: Process all images automatically with --auto flag
• Flexible Configuration: Customizable quality, max size, and directory options
• Progress Tracking: Shows file size reduction and processing statistics

Installation

Prerequisites

ImageMagick is required for image processing:

# Ubuntu/Debian
sudo apt-get install imagemagick

# macOS
brew install imagemagick

# Windows WSL
sudo apt-get install imagemagick

Download Script

# Clone the repository
git clone git@github.com:kitikonti/script-image-optimizer.git
cd script-image-optimizer

# Make script executable
chmod +x optimize-images.sh

Usage

Basic Usage

# Interactive mode - process all images (default)
./optimize-images.sh

# Automatic mode - process all images without prompts
./optimize-images.sh --auto

# Git mode - only process staged images (respects .gitignore)
git add . && ./optimize-images.sh --git-only

# Process specific directory
./optimize-images.sh --auto /path/to/images/

Advanced Options

# Custom quality setting (1-100)
./optimize-images.sh --quality 90

# Custom maximum image size
./optimize-images.sh --max-size 2048

# Keep metadata instead of stripping
./optimize-images.sh --keep-metadata

# Combine options
./optimize-images.sh --auto --quality 90 --max-size 2048 --keep-metadata

Command Line Options

Option	Description	Default
--auto	Process all images without asking for confirmation	Interactive mode
--interactive	Ask for confirmation for each image	Default
--keep-metadata	Preserve image metadata (EXIF, GPS, etc.)	Strip metadata
--quality N	Set JPEG quality (1-100)	85
--max-size N	Set maximum image dimension in pixels	3840
--git-only	Only process staged images in git repositories	Process all images
--help	Show help message	-

Examples

Web Development Workflow

# Git-aware workflow (recommended for repositories)
git add .
./optimize-images.sh --git-only --auto
git commit -m "Add optimized images"

# Simple workflow (process all images)
./optimize-images.sh --auto --quality 85 --max-size 3840
git add .
git commit -m "Add optimized images"

Photography Workflow

# Process photos while keeping metadata
./optimize-images.sh --keep-metadata --quality 95 --max-size 4096

# Interactive processing for selective optimization
./optimize-images.sh --interactive --quality 90

Batch Processing

# Process multiple directories
for dir in images/ photos/ assets/; do
    ./optimize-images.sh --auto "$dir"
done

How the Script Works

Default Mode

1. Finds All Images: Locates all .jpg, .jpeg, and .png files in directory
2. Simple Processing: Processes everything regardless of git status
3. Universal: Works anywhere, no git required
4. Predictable: Users expect this behavior by default

Git Mode (--git-only flag)

1. Requires Staging: Run git add . first to stage files
2. Finds Staged Images: Locates staged .jpg, .jpeg, and .png files
3. Respects .gitignore: Only processes files that git would track
4. Safe for Repos: Prevents processing build artifacts or ignored files

Processing Steps

1. Analyzes: Checks file size, dimensions, and determines optimization needs
2. Resizes: Reduces images larger than max size while maintaining aspect ratio
3. Optimizes: Compresses images to specified quality level
4. Strips Metadata: Removes EXIF, GPS, and other metadata (unless --keep-metadata is used)
5. Reports: Shows file size reduction and processing statistics

Output Example

============================================
Image Optimization Script
============================================

Directory: /home/user/project/images
Found 3 image(s)

This script will:
  • Resize images larger than 3840px to fit within 3840x3840
  • Optimize all images to 85% quality
  • Strip metadata (EXIF, GPS, etc.)

Mode: Automatic (will process all images)

----------------------------------------
Image: photo1.jpg
Current: 5234KB, 5472x3648
Actions:
  • Resize to approximately 3840x2560
  • Optimize to 85% quality
  • Strip metadata
✓ Optimized: 5234KB → 1456KB (-72%)

----------------------------------------
Image: photo2.jpg
Current: 2341KB, 3000x2000
Actions:
  • No resize needed (within 3840x3840)
  • Optimize to 85% quality
  • Strip metadata
✓ Optimized: 2341KB → 1234KB (-47%)

============================================
Summary:
  • Processed: 3 image(s)
  • Skipped: 0 image(s)
  • Total size: 9876KB → 4123KB (-58%)

Git Integration

Default vs Git Mode

Default Mode (./optimize-images.sh):

• ✅ Processes all images in directory
• ✅ Simple and predictable
• ✅ Works anywhere (no git required)
• ❌ May process build artifacts or temporary files

Git Mode (./optimize-images.sh --git-only):

• ✅ Only processes staged images
• ✅ Respects .gitignore automatically
• ✅ Safe for repositories
• ❌ Requires git add . first

Git Mode Workflow

# 1. Stage all trackable files
git add .

# 2. Optimize only staged images
./optimize-images.sh --git-only --auto

# 3. Check results and commit
git status
git commit -m "Add optimized images"

Why Git Mode Requires Staging

1. Fresh Repositories: git status only shows directories like source/, not individual files
2. Respects .gitignore: Staged files exclude gitignored items automatically
3. Covers All Cases: Works for new files, modified files, and fresh repositories
4. Safe Processing: Only optimizes files that will actually be tracked by git

Safety Features

• Non-destructive: Modifies images in place but asks for confirmation in interactive mode
• Error Handling: Gracefully handles missing files and invalid images
• Requirement Checking: Verifies ImageMagick and git (if needed) are installed
• Directory Validation: Ensures target directory exists before processing

Use Cases

Web Development

• Optimize images before committing to git
• Reduce website loading times
• Maintain consistent image quality across projects

Photography

• Batch process photos for web sharing
• Reduce file sizes for email or upload
• Maintain quality while reducing storage needs

General File Management

• Clean up image directories
• Prepare images for sharing or archiving
• Standardize image sizes across collections

Integration Examples

Pre-commit Hook

#!/bin/bash
# .git/hooks/pre-commit

# Check for staged images and optimize them
staged_images=$(git diff --cached --name-only --diff-filter=A | grep -E '\.(jpg|jpeg|png)$')
if [ ! -z "$staged_images" ]; then
    echo "Optimizing staged images..."
    ./scripts/optimize-images.sh --git-only --auto
    # Re-stage the optimized images
    git add .
fi

Build Process

# In your build script - process all images in source directory
./optimize-images.sh --auto src/images/

Deployment Pipeline

# Before deployment
./optimize-images.sh --auto --quality 80 --max-size 2048 assets/

Troubleshooting

ImageMagick Not Found

# Install ImageMagick
sudo apt-get install imagemagick  # Ubuntu/Debian
brew install imagemagick          # macOS

Permission Denied

# Make script executable
chmod +x optimize-images.sh

Git Not Found (--git-only mode)

# Install git
sudo apt-get install git

Contributing

Contributions are welcome! Please feel free to submit issues and enhancement requests.

License

This script is released under the MIT License. See LICENSE file for details.

Author

Created for use in web development and photography workflows. Part of the BitToGit migration helper project suite.