How JPG compression works
JPG splits a picture into small blocks and keeps the detail that the eye notices most. The quality number sets how much of the rest is thrown away. A lower number means a smaller file and more visible blocks, mostly around sharp edges and in smooth gradients.
Which JPG quality should you use?
| Quality | Result | Use it for |
|---|---|---|
| 90 to 100 | Very large files for a small gain | Archives, print masters |
| 80 to 85 | Looks the same as the original at normal size | Websites, portfolios, shops |
| 70 to 75 | Small files, slight softness on close look | Blog images, email, galleries |
| 50 to 60 | Visible blocks around edges | Thumbnails, strict size limits |
| Below 40 | Clearly blocky | Avoid |
Tips for smaller JPG files
- Resize first. A 4,000 pixel photo shown at 1,000 pixels wastes most of its bytes.
- Compress once. Each save of a JPG adds damage. Keep the original and compress that.
- Remove metadata. Re-encoding drops EXIF data, including the GPS position, which also helps privacy.
- Mind the picture. Noise and fine texture compress poorly. Smooth areas compress well.
Need a fixed limit? Try 100 KB, 200 KB or 1 MB. For a smaller site, convert to WebP with the JPG to WebP converter. Other formats: JPEG, PNG, WebP, HEIC, AVIF.