How to Optimize Images for Websites – Complete Guide
Published: March 2025 • 5 min read
Why Image Optimization Matters
Images make up 50-70% of total page weight on most websites. Unoptimized images are the #1 cause of slow page load times. Google uses page speed as a ranking factor, so faster images mean better SEO rankings and more traffic.
Image Optimization Checklist
- Resize to display size: Never serve a 4000px image that displays at 800px. Use our Image Resizer.
- Compress aggressively: Use 60-80% quality for JPGs. Most users cannot tell the difference. Try our Image Compressor.
- Use WebP format: 25-34% smaller than JPG. Convert with our WebP Converter.
- Add lazy loading: Use loading="lazy" on img tags below the fold.
- Use responsive images: Serve different sizes for different screens using srcset.
Target File Sizes
- Hero images: under 200KB
- Blog images: under 100KB
- Thumbnails: under 30KB
- Icons: under 10KB (use SVG when possible)