ImageMagick Skill

When to Use

• Convert images between formats (JPEG, PNG, WebP, AVIF, etc.)
• Resize images (thumbnails, responsive images, optimization)
• Rotate or flip images
• Apply filters and effects (blur, sharpen, adjust colors, etc.)
• Batch process multiple images
• Create image composites or combine images
• Extract image metadata or information
• Optimize images for web (compression, format conversion)
• Generate image variants (different sizes, formats)

Core Commands

Basic Conversion

magick input.jpg output.png                    # Convert format
magick input.png output.webp                   # Convert to WebP
magick input.jpg -resize 50% output.jpg        # Resize to 50%
magick input.jpg -rotate 90 output.jpg        # Rotate 90 degrees

Reading Image Information

magick identify image.jpg                      # Get image info
magick identify -format "%wx%h" image.jpg     # Get dimensions
magick identify -format "%[size]" image.jpg    # Get file size

Common Operations

Resize

• magick input.jpg -resize 800x600 output.jpg

  - Resize to exact dimensions

• magick input.jpg -resize 50% output.jpg

  - Resize by percentage

• magick input.jpg -resize 800x600^ output.jpg

  - Resize to fit (maintain aspect)

• magick input.jpg -resize 800x600\> output.jpg

  - Only resize if larger

• magick input.jpg -thumbnail 200x200 output.jpg

  - Create thumbnail

Rotate

• magick input.jpg -rotate 90 output.jpg

  - Rotate 90° clockwise

• magick input.jpg -rotate -90 output.jpg

  - Rotate 90° counter-clockwise

• magick input.jpg -rotate 45 output.jpg

  - Rotate 45°

• magick input.jpg -flip output.jpg

  - Flip vertically

• magick input.jpg -flop output.jpg

  - Flip horizontally

Format Conversion

• magick input.jpg output.png

  - JPEG to PNG

• magick input.png output.webp

  - PNG to WebP

• magick input.jpg output.avif

  - JPEG to AVIF

• magick input.png -quality 85 output.jpg

  - PNG to JPEG with quality

Quality & Compression

• magick input.jpg -quality 85 output.jpg

  - Set JPEG quality (1-100)

• magick input.png -quality 90 output.webp

  - Set WebP quality

• magick input.jpg -strip output.jpg

  - Remove metadata (reduce size)

• magick input.jpg -sampling-factor 4:2:0 output.jpg

  - Optimize JPEG

Filters & Effects

• magick input.jpg -blur 0x2 output.jpg

  - Apply blur

• magick input.jpg -sharpen 0x1 output.jpg

  - Sharpen image

• magick input.jpg -brightness-contrast 10x5 output.jpg

  - Adjust brightness/contrast

• magick input.jpg -modulate 100,150,100 output.jpg

  - Adjust brightness, saturation, hue

• magick input.jpg -grayscale output.jpg

  - Convert to grayscale

• magick input.jpg -sepia-tone 80% output.jpg

  - Apply sepia effect

Cropping

• magick input.jpg -crop 800x600+100+50 output.jpg

  - Crop (width x height + x + y)

• magick input.jpg -crop 50%x50%+25%+25% output.jpg

  - Crop by percentage

• magick input.jpg -gravity center -crop 800x600+0+0 output.jpg

  - Center crop

Batch Processing

• magick *.jpg -resize 50% resized_%d.jpg

  - Resize all JPGs

• magick *.png -quality 85 converted_%d.jpg

  - Convert all PNGs to JPEG

• magick input*.jpg -append output.jpg

  - Append images vertically

• magick input*.jpg +append output.jpg

  - Append images horizontally

Common Use Cases

Web Optimization

# Convert to WebP with quality optimization
magick input.jpg -quality 85 -strip output.webp

# Create responsive image sizes
magick input.jpg -resize 1920x1080\> large.jpg
magick input.jpg -resize 1280x720\> medium.jpg
magick input.jpg -resize 640x360\> small.jpg

# Generate thumbnail
magick input.jpg -thumbnail 200x200 -strip thumb.jpg

Format Conversion

# JPEG to PNG (preserve transparency)
magick input.jpg output.png

# PNG to JPEG (with white background)
magick input.png -background white -flatten output.jpg

# Convert to AVIF (modern format)
magick input.jpg -quality 90 output.avif

Image Manipulation

# Rotate and resize
magick input.jpg -rotate 90 -resize 50% output.jpg

# Apply multiple effects
magick input.jpg -brightness-contrast 10x5 -sharpen 0x1 output.jpg

# Create composite
magick background.jpg logo.png -gravity center -composite output.jpg

Best Practices

1. Use

   magick

   command - Modern ImageMagick uses

   magick

   (not

   convert

   )
2. Preserve aspect ratio - Use

   \>

   or

   ^

   modifiers when resizing
3. Strip metadata - Use

   -strip

   for web images to reduce file size
4. Quality settings - Use 80-90 for JPEG, 85-95 for WebP
5. Batch operations - Use wildcards and

   %d

   for sequential numbering
6. Check before processing - Use

   identify

   to verify image properties
7. Optimize for web - Combine

   -strip

   ,

   -quality

   , and format conversion

Command Aliases

• magick

  - Modern command (recommended)

• convert

  - Legacy alias (still works)

• identify

  - Get image information

• mogrify

  - In-place image modification

Installation

# macOS
brew install imagemagick

# Linux
sudo apt-get install imagemagick  # Debian/Ubuntu
sudo yum install ImageMagick      # RHEL/CentOS

# Verify installation
magick --version

References

• Official Documentation: https://imagemagick.org/script/convert.php
• Command-line Options: https://imagemagick.org/script/command-line-options.php
• Examples: https://imagemagick.org/script/examples.php