How to Optimize Images for the Web

· Category: Web Performance

Short answer

Optimized images reduce page weight without sacrificing quality. Use modern formats, responsive sizing, and compression tools.

Steps

  1. Convert images to WebP or AVIF for better compression than JPEG or PNG.
  2. Use srcset and sizes to serve different resolutions based on viewport.
  3. Compress images with tools like Squoosh, ImageOptim, or Sharp.
  4. Implement lazy loading for below-the-fold images.
  5. Use a CDN with automatic image optimization.

Tips

  • Serve SVGs for icons and simple graphics; they scale without quality loss.
  • Consider using an image CDN like Cloudinary or Imgix for on-the-fly optimization.
  • Always specify width and height to prevent layout shifts.

Common issues

  • Over-compression causes visible artifacts in photographs.
  • Art direction requires <picture> elements, adding markup complexity.