Images account for most of a page's weight. Proper optimization dramatically improves load times without sacrificing visual quality.
Image Formats#
JPEG
- Best for: Photographs
- Lossy compression
- No transparency
- Wide support
PNG
- Best for: Graphics, screenshots
- Lossless compression
- Supports transparency
- Larger file sizes
WebP
- Best for: Modern browsers
- 25-35% smaller than JPEG
- Supports transparency
- 95%+ browser support
AVIF
- Best for: Maximum compression
- 50% smaller than JPEG
- Slower encoding
- Growing browser support (~90%)
SVG
- Best for: Icons, logos
- Vector format (scales infinitely)
- Can be styled with CSS
- Inline-able in HTML
Format Selection#
Responsive Images#
Lazy Loading#
Compression Tools#
Next.js Image Component#
Placeholder Strategies#
SVG Optimization#
Performance Checklist#
Monitoring#
Conclusion#
Image optimization is one of the highest-impact performance improvements you can make. Use modern formats, serve responsive sizes, lazy load below-the-fold images, and preload critical ones.
Your users on slow connections will thank you.