How to Compress Images for the Web
Learn how to reduce image file sizes for faster web page loading without visible quality loss. This guide covers lossy and lossless compression techniques, format selection, and recommended quality settings.
Nén Ảnh
Giảm dung lượng ảnh mà vẫn giữ chất lượng.
Why Image Compression Matters
Images typically account for 50-75% of a web page's total size. Unoptimized images slow page loads, hurt Core Web Vitals scores, and increase bandwidth costs. Proper compression can reduce image sizes by 60-80% with minimal visible quality loss.
Lossy vs Lossless Compression
Lossy compression (JPEG, WebP lossy) permanently removes data humans are unlikely to notice. A JPEG at quality 82-85 is visually indistinguishable from the original for most photographs.
Lossless compression (PNG, WebP lossless) reduces file size without removing any data. Best for screenshots, logos, and images with text.
Recommended Settings
| Format | Quality | Use Case |
|---|---|---|
| JPEG | 80-85 | Photographs |
| WebP | 75-82 | All image types |
| PNG | Max compression | Screenshots, logos |
| AVIF | 60-70 | Modern browsers |
Quick Steps
- Choose the right format for your content type
- Resize to the maximum display dimensions needed
- Apply compression at the recommended quality level
- Compare original and compressed versions side by side
- Verify the file size reduction meets your target