Picking a quality setting
| Quality | Use for | Visible loss? |
|---|---|---|
| 85–90 | Product photography, fine gradients | None |
| 75–85 | Most web content — the default | Effectively none |
| 65–75 | Backgrounds, decorative images | Rarely noticed |
| Below 65 | Only when size dominates everything | Yes — blocking and halos |
The generational loss trap
JPEG discards detail every time it is saved, not just the first time. Open a JPEG, edit it, save it, then repeat, and the damage accumulates in a way that cannot be undone — edges pick up halos and flat areas turn blotchy, and no later setting recovers them.
- Always compress from the highest-quality original you hold, never from an already-compressed copy.
- Resize and change quality in one pass rather than saving in between.
- Do not re-save at quality 95 hoping to protect an image — the detail is already gone, and the file just gets bigger.
- Keep a master copy in a lossless format if the image will be edited repeatedly.
Resize before you compress
A photo straight off a phone is often 4000 pixels wide and displayed in an 800 pixel column. Because file size tracks pixel area, that image is carrying roughly 25 times more data than the page can show, and no quality setting fixes it. Run it through the image resizer first, then come back here. The full order is in how to reduce image file size.
Frequently Asked Questions
How do I reduce the file size of a JPEG?
Resize it first if its pixel dimensions are larger than the space it is shown in, then re-save at a quality between 75 and 85. That band typically removes 40 to 70 percent of the file with no difference most people can see. Doing it in that order matters, because compressing an image you are about to shrink wastes the effort.
What quality setting should I use for JPEG?
Start at 80. Drop to 65 to 75 for backgrounds and decorative images where fine detail does not matter. Stay at 85 for product photography or anything with subtle gradients. Above 90 the file grows steeply for almost no visible gain, which is why so many images on the web are needlessly heavy.
Does compressing a JPEG more than once make it worse?
Yes, and this is the one property of JPEG worth internalising. It is lossy on every save, not just the first, so each round of decode-and-re-encode discards a little more detail permanently. Always compress from the highest-quality original you have rather than from a copy you already compressed, and avoid re-saving the same file repeatedly.
Can I compress a JPEG without losing any quality?
Not with the quality slider — lossy compression always discards some data by definition. If you truly need zero loss, resizing is the lever to use, because scaling down removes pixels the display never had room for rather than degrading the ones you keep. In practice, quality 80 is visually lossless for almost all photographic content.
Should this image be a JPEG at all?
JPEG is built for photographs and handles them beautifully. It is a poor choice for screenshots, logos, line art or anything with sharp text, where its compression produces visible halos and smearing around edges. Use PNG or WebP for those instead.
Are my images uploaded to a server?
No. Decoding and re-encoding run in a Web Worker on your own device using WebAssembly builds of the standard image libraries. Your photos never leave your browser, which you can verify in the Network tab while compressing.
Related tools
- Image compressor — the same engine for PNG and WebP too.
- Compress PNG — where a quality slider does almost nothing, and why.
- JPG to WebP — typically another 25–35% at the same quality.
- JPEG to JPG — if you only need the extension changed, with no re-encoding.