Why Compress Images?
Images are typically the largest assets on a web page, often accounting for 50-80% of total page weight. Compressing images reduces file size, resulting in faster page loads, lower bandwidth costs, and better Core Web Vitals scores — all of which directly impact user experience and SEO rankings.
Lossy vs Lossless Compression
| Lossy | Lossless | |
|---|---|---|
| How it works | Permanently removes data | Reorganizes data without loss |
| File size reduction | High (60-80%) | Low-medium (10-30%) |
| Quality | Slightly reduced | Identical to original |
| Best for | Photos, complex images | Logos, icons, screenshots |
| Formats | JPEG, WebP | PNG, WebP, GIF |
Image Format Guide
JPEG
- Best for photographs and complex images with many colors
- Lossy compression — quality setting 75-85% is usually indistinguishable
- Does not support transparency
- Universal browser support
PNG
- Best for images requiring transparency (logos, icons)
- Lossless compression — exact reproduction
- Larger file size than JPEG for photos
- Supports alpha transparency
WebP
- Modern format developed by Google
- 25-34% smaller than JPEG at equivalent quality
- Supports both lossy and lossless compression
- Supports transparency
- Supported by all modern browsers
Recommended Quality Settings
| Use Case | Format | Quality | Expected Savings |
|---|---|---|---|
| Hero images | WebP | 80-85% | 40-60% |
| Product photos | WebP/JPEG | 75-80% | 50-70% |
| Thumbnails | WebP/JPEG | 70-75% | 60-80% |
| Logos/Icons | SVG/PNG | Lossless | 10-30% |
✓ Quick tip: Use WebP as your primary format. Serve it with a PNG/JPEG fallback for browsers that don't support WebP. Most modern websites now default to WebP, saving 25-35% in bandwidth compared to JPEG.