JPEG is still the file people mean when they say “photo”. Phones, scanners and older cameras emit it, and every browser displays it. It is a lossy format: each save can throw away a little more. Compress from the original, once.
MozJPEG, the encoder behind this page, usually beats the JPEG writer built into phones at the same visual quality. Quality 80 is the right first try for a blog or a shop. Quality 90 is for a crop you will view large. Below 60, blocks show up in skies and walls.
How to compress a JPEG
Add JPEG files
Drop .jpg or .jpeg photos here. Other formats in the same batch are converted only if you change the output menu; otherwise each file keeps its own format.
Set JPEG quality
80 is the default. If a form demands a weight, switch on a target size and the page will search for a quality that fits.
Check edges and skies
Use the comparison slider. If text or a face looks soft, raise the quality or reduce the pixel size instead of crushing the number.
When JPEG is the right output
Email and forms
Support desks and application portals almost always accept JPEG. A 6 MB scan of a document becomes manageable without becoming a PDF.
Older websites
If you cannot serve WebP or AVIF, a well-encoded JPEG is still the dependable choice.
Do not recompress the same JPEG
Opening a JPEG, saving it, and saving it again compounds artifacts. Keep the camera original, and export the small copy from that file. If you need to edit, edit a PNG or the raw file, then export JPEG at the end.
JPEG quality guide
| Quality | Use | What you notice |
|---|---|---|
| 90–100 | Large display, print-ish crops | Little change, modest savings |
| 75–89 | Web, social, email | Clean to most people, large savings |
| 60–74 | Thumbnails and previews | Soft detail, much smaller files |
| Below 60 | Only when size wins | Block edges in flat color |
JPEG compression questions
How do I compress JPEG images without losing the photo?
Use quality 75–85 and, if the pixel dimensions are larger than you display, resize as well. That combination usually keeps the photo looking right while cutting most of the weight.
Is MozJPEG different from a normal JPEG?
The file is still a standard JPEG that opens everywhere. MozJPEG spends more effort choosing how to encode it, so the file is often smaller at the same quality number.
Why is my JPEG barely smaller?
The camera may already have saved it at a low quality. Re-encoding cannot invent detail, and a second pass at a similar quality saves little. Resize the pixels if you need a real drop.
Can I turn a PNG into a JPEG here?
Yes. Set the output format to JPEG. Transparency becomes a flat background because JPEG has no alpha channel.