Img Optimizer

Image Optimizer

Optimize images via compression, resizing, and format conversion.

Use when compressing images, batch converting formats, or resizing for web/social media.

Requirements

• ImageMagick 7+ (magick) or ImageMagick 6 (convert)
• Optional: cwebp (WebP), optipng (PNG), jpegoptim (JPEG)
• No API keys needed

Instructions

1. Check image info before processing:

   magick identify -format "%f | %wx%h | %b | %m\n" image.png
   

2. Compress — reduce file size:

   # JPEG (80% quality is a good default)
   magick input.jpg -quality 80 -strip output.jpg
   
   # PNG (lossless optimization)
   optipng -o5 image.png          # in-place
   magick input.png -strip output.png
   
   # WebP (lossy, excellent compression)
   cwebp -q 80 input.png -o output.webp
   

3. Resize — scale to specific dimensions:

   # Exact dimensions (may distort)
   magick input.jpg -resize 800x600! output.jpg
   
   # Fit within bounds (preserve aspect ratio)
   magick input.jpg -resize 800x600 output.jpg
   
   # By percentage
   magick input.jpg -resize 50% output.jpg
   
   # Thumbnail (crop to fill)
   magick input.jpg -resize 300x300^ -gravity center -extent 300x300 thumb.jpg
   

4. Format conversion:

   magick input.png output.webp    # PNG → WebP
   magick input.jpg output.avif    # JPEG → AVIF
   

5. Batch processing:

   # Convert all PNGs to WebP in a directory
   for f in *.png; do magick "$f" -quality 80 "${f%.png}.webp"; done
   
   # Resize all images to max 1200px width
   for f in *.jpg; do magick "$f" -resize "1200>" "$f"; done
   

6. Output format — report results:

   ## 🖼️ Optimization Results
   | File | Original | Optimized | Savings |
   |------|----------|-----------|---------|
   | hero.jpg | 2.4 MB | 680 KB | 72% |
   | logo.png | 340 KB | 89 KB | 74% |
   **Total: 2.74 MB → 769 KB (72% reduction)**
   

Preset Sizes

Edge Cases

• Animated GIF: Use magick input.gif -coalesce -resize 50% output.gif (preserve animation).
• EXIF data: -strip removes metadata including GPS. Use -auto-orient -strip to preserve rotation.
• Transparency: Converting PNG (with alpha) to JPEG loses transparency. Add -background white -flatten.
• Very large files: Process in batches to avoid memory issues.
• Already optimized: Check if compression actually reduces size — skip if negligible.

Security

• Sanitize filenames before processing — avoid shell injection via crafted filenames.
• Use magick not convert to avoid path conflicts with Windows convert.exe.