optimize-images.sh

#!/bin/bash

# ============================================================================
# Image Optimization Script
# ============================================================================
# 
# Purpose:
#   Optimizes image files to reduce size while maintaining quality.
#   - Resizes images larger than 3840px (width or height) to fit within 3840x3840
#   - Optimizes all images to 85% JPEG quality
#   - Strips metadata by default (for privacy and file size)
#
# Usage:
#   ./optimize-images.sh [options] [directory]
#
# Options:
#   --auto           Process all images without asking for confirmation
#   --interactive    Ask for confirmation for each image (default)
#   --keep-metadata  Preserve image metadata (default: strip metadata)
#   --quality N      Set JPEG quality (1-100, default: 85)
#   --max-size N     Set maximum image dimension (default: 3840)
#   --git-only       Only process staged images in git repositories
#   --help           Show this help message
#
# Directory:
#   Path to directory containing images (default: current directory)
#
# Examples:
#   ./optimize-images.sh                            # Interactive mode, all images
#   ./optimize-images.sh --auto                     # Auto mode, all images
#   git add . && ./optimize-images.sh --git-only    # Process only staged git images
#   ./optimize-images.sh --quality 90               # Custom quality, all images
#   ./optimize-images.sh --max-size 2048 --auto     # Custom settings, all images
#
# Requirements:
#   - ImageMagick (install with: sudo apt-get install imagemagick)
#   - Git (optional, only needed for --git-only mode)
#
# IMPORTANT: For --git-only mode, run 'git add .' first to stage files.
# This allows the script to detect new/modified images while respecting .gitignore.
#
# ============================================================================

# Default settings
INTERACTIVE=true
STRIP_METADATA=true
QUALITY=85
MAX_SIZE=3840
GIT_ONLY=false
DIRECTORY="."

# Parse command line arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        --auto)
            INTERACTIVE=false
            shift
            ;;
        --interactive)
            INTERACTIVE=true
            shift
            ;;
        --keep-metadata)
            STRIP_METADATA=false
            shift
            ;;
        --quality)
            if [[ $2 =~ ^[0-9]+$ ]] && [ $2 -ge 1 ] && [ $2 -le 100 ]; then
                QUALITY=$2
                shift 2
            else
                echo "Error: Quality must be a number between 1 and 100"
                exit 1
            fi
            ;;
        --max-size)
            if [[ $2 =~ ^[0-9]+$ ]] && [ $2 -ge 100 ]; then
                MAX_SIZE=$2
                shift 2
            else
                echo "Error: Max size must be a number >= 100"
                exit 1
            fi
            ;;
        --git-only)
            GIT_ONLY=true
            shift
            ;;
        --help)
            head -n 40 "$0" | grep "^#" | sed 's/^# \?//'
            exit 0
            ;;
        -*)
            echo "Unknown option: $1"
            echo "Use --help for usage information"
            exit 1
            ;;
        *)
            DIRECTORY="$1"
            shift
            ;;
    esac
done

# Check requirements
if ! command -v mogrify &> /dev/null; then
    echo "Error: ImageMagick is not installed."
    echo ""
    echo "Please install ImageMagick:"
    echo "  Ubuntu/Debian: sudo apt-get install imagemagick"
    echo "  macOS: brew install imagemagick"
    echo "  Windows WSL: sudo apt-get install imagemagick"
    exit 1
fi

if ! command -v identify &> /dev/null; then
    echo "Error: ImageMagick 'identify' command not found."
    echo "Please ensure ImageMagick is properly installed."
    exit 1
fi

if [ "$GIT_ONLY" = true ]; then
    if ! command -v git &> /dev/null; then
        echo "Error: Git is not installed (required for --git-only mode)."
        exit 1
    fi
    
    if ! git rev-parse --git-dir > /dev/null 2>&1; then
        echo "Error: Not in a git repository (required for --git-only mode)."
        echo "Please run this script from within your project directory or remove --git-only."
        exit 1
    fi
fi

# Check if directory exists
if [ ! -d "$DIRECTORY" ]; then
    echo "Error: Directory '$DIRECTORY' does not exist."
    exit 1
fi

# Change to target directory
cd "$DIRECTORY" || exit 1

# Find images based on mode
if [ "$GIT_ONLY" = true ]; then
    # Git mode: Find staged and modified images in git repository
    # This requires running 'git add .' first to stage files
    images=$(git status --porcelain | grep -E '^A |^M ' | grep -E '\.(jpg|jpeg|png)$' | awk '{print $2}')
    
    # If no staged images found, suggest running git add
    if [ -z "$images" ]; then
        echo "No staged images found."
        echo ""
        echo "IMPORTANT: You need to stage files first with 'git add .' to detect images."
        echo "This allows the script to find new and modified images while respecting .gitignore."
        echo ""
        echo "Run: git add . && ./optimize-images.sh --git-only [options]"
        echo "Or use: ./optimize-images.sh (to process all images regardless of git status)"
        exit 0
    fi
else
    # Default: Find all images in directory
    images=$(find . -name "*.jpg" -o -name "*.jpeg" -o -name "*.png" | sed 's|^\./||')
fi

if [ -z "$images" ]; then
    if [ "$GIT_ONLY" = true ]; then
        echo "No staged images found."
    else
        echo "No images found in directory: $DIRECTORY"
    fi
    exit 0
fi

# Count images
image_count=$(echo "$images" | wc -l)

# Show what the script will do
echo "============================================"
echo "Image Optimization Script"
echo "============================================"
echo ""
echo "Directory: $(pwd)"
echo "Found $image_count image(s)"
echo ""
echo "This script will:"
echo "  • Resize images larger than ${MAX_SIZE}px to fit within ${MAX_SIZE}x${MAX_SIZE}"
echo "  • Optimize all images to ${QUALITY}% quality"
if [ "$STRIP_METADATA" = true ]; then
    echo "  • Strip metadata (EXIF, GPS, etc.)"
else
    echo "  • Keep metadata"
fi
echo ""

if [ "$INTERACTIVE" = true ]; then
    echo "Mode: Interactive (will ask for each image)"
else
    echo "Mode: Automatic (will process all images)"
fi
echo ""

# Process statistics
total_before=0
total_after=0
processed_count=0
skipped_count=0

# Process each image
for img in $images; do
    # Check if file exists (in case it was deleted after finding)
    if [ ! -f "$img" ]; then
        echo "Warning: $img no longer exists, skipping."
        ((skipped_count++))
        continue
    fi
    
    # Get file info
    size_before=$(stat -f%z "$img" 2>/dev/null || stat -c%s "$img" 2>/dev/null || echo "0")
    size_kb=$(( size_before / 1024 ))
    
    # Get image dimensions
    dimensions=$(identify -format "%wx%h" "$img" 2>/dev/null || echo "unknown")
    width=$(echo "$dimensions" | cut -d'x' -f1)
    height=$(echo "$dimensions" | cut -d'x' -f2)
    
    # Determine if resize is needed
    needs_resize=false
    new_dimensions=""
    if [[ "$width" =~ ^[0-9]+$ ]] && [[ "$height" =~ ^[0-9]+$ ]]; then
        if [ "$width" -gt "$MAX_SIZE" ] || [ "$height" -gt "$MAX_SIZE" ]; then
            needs_resize=true
            # Calculate new dimensions maintaining aspect ratio
            if [ "$width" -gt "$height" ]; then
                new_width=$MAX_SIZE
                new_height=$(( (height * MAX_SIZE) / width ))
            else
                new_height=$MAX_SIZE
                new_width=$(( (width * MAX_SIZE) / height ))
            fi
            new_dimensions="${new_width}x${new_height}"
        fi
    fi
    
    # Show image info
    echo "----------------------------------------"
    echo "Image: $img"
    echo "Current: ${size_kb}KB, ${dimensions}"
    
    # Show what will be done
    echo "Actions:"
    if [ "$needs_resize" = true ]; then
        echo "  • Resize to approximately $new_dimensions"
    else
        echo "  • No resize needed (within ${MAX_SIZE}x${MAX_SIZE})"
    fi
    echo "  • Optimize to ${QUALITY}% quality"
    if [ "$STRIP_METADATA" = true ]; then
        echo "  • Strip metadata"
    else
        echo "  • Keep metadata"
    fi
    
    # Ask for confirmation if in interactive mode
    if [ "$INTERACTIVE" = true ]; then
        echo -n "Process this image? [Y/n/q] "
        read -r answer
        
        case "$answer" in
            [nN])
                echo "Skipped."
                ((skipped_count++))
                continue
                ;;
            [qQ])
                echo ""
                echo "Quitting. Processed $processed_count image(s), skipped $skipped_count."
                exit 0
                ;;
        esac
    fi
    
    # Build mogrify command arguments
    mogrify_args=()
    
    # Add resize if needed
    if [ "$needs_resize" = true ]; then
        mogrify_args+=("-resize" "${MAX_SIZE}x${MAX_SIZE}>")
    fi
    
    # Add quality setting
    mogrify_args+=("-quality" "$QUALITY")
    
    # Add strip metadata if requested
    if [ "$STRIP_METADATA" = true ]; then
        mogrify_args+=("-strip")
    fi
    
    # Execute the command with proper argument handling
    mogrify "${mogrify_args[@]}" "$img"
    
    if [ $? -eq 0 ]; then
        # Get new size
        size_after=$(stat -f%z "$img" 2>/dev/null || stat -c%s "$img" 2>/dev/null || echo "0")
        
        # Calculate reduction
        if [ "$size_before" -gt 0 ]; then
            reduction=$(( ((size_before - size_after) * 100) / size_before ))
        else
            reduction=0
        fi
        
        # Update totals
        total_before=$((total_before + size_before))
        total_after=$((total_after + size_after))
        ((processed_count++))
        
        echo "✓ Optimized: $(( size_before / 1024 ))KB → $(( size_after / 1024 ))KB (-${reduction}%)"
    else
        echo "✗ Error processing image"
        ((skipped_count++))
    fi
done

# Show summary
echo ""
echo "============================================"
echo "Summary:"
echo "  • Processed: $processed_count image(s)"
echo "  • Skipped: $skipped_count image(s)"
if [ "$processed_count" -gt 0 ] && [ "$total_before" -gt 0 ]; then
    total_reduction=$(( ((total_before - total_after) * 100) / total_before ))
    echo "  • Total size: $(( total_before / 1024 ))KB → $(( total_after / 1024 ))KB (-${total_reduction}%)"
fi
echo ""

if [ "$GIT_ONLY" = true ]; then
    echo "Use 'git status' to see the changes."
    echo "Use 'git add' to stage the optimized images."
else
    echo "All images in directory processed."
fi