JPG

Compress JPG

Up to 100 files at once. Mixed formats are fine.

Compressing a JPG re-encodes the photograph so it keeps fewer bytes of detail the eye was not using. Drop a file above and it happens inside your browser — nothing is uploaded. You will usually save between half and four fifths of the size before anything becomes visible, and if the file is already as small as it sensibly gets, we hand it back untouched rather than pretend.

  • Where it runsIn your browser. The file is never uploaded, and it works offline.
  • You set the tradeQuality against size is a slider, and the JPG is re-encoded only once.
  • Nothing is keptNo account, no upload, no copy on a server — there is no server in this path.

Compress JPG

Why a JPG can shrink so much without looking different

JPEG does not store a picture as pixels. It breaks the image into blocks, describes each one as a set of frequencies — broad shapes first, fine detail last — and then rounds off the fine end. The quality setting is nothing more than how aggressively it rounds.

That works because human vision is far more sensitive to brightness than to colour, and far more sensitive to edges than to texture. A photograph saved at quality 95 is keeping detail nobody can see under any normal viewing condition, which is why dropping to 75 typically removes half to three quarters of the file and leaves an image most people cannot tell apart from the original.

Resizing usually beats compressing

The most common reason a photograph is too large is not its quality but its dimensions. A modern phone produces images around 4000 pixels wide. If that picture is going into an email, a document or a web page, it will be displayed at perhaps a quarter of that — and the other three quarters are bytes carried around for nothing.

Halving the width quarters the pixel count, and the file follows. The resize control under the result does this, and combining a modest resize with a modest quality drop almost always produces a better-looking file at a given size than pushing quality alone. If the image is destined for print, leave the size alone: there the pixels are the point.

The compression that already happened

Every JPG has been compressed once already, when it was saved. Compressing again does not resume from the original scene — it works from what survived, and rounds that off further. This is why repeatedly saving a JPEG degrades it: each pass is lossy, and the losses accumulate.

In practice one careful pass costs almost nothing, because the second rounding mostly discards detail the first one had already coarsened. What does hurt is a chain of them, so if the original is still somewhere, compress that rather than a copy that has been through three tools.

When we give the file back unchanged

A JPEG saved at quality 60 and re-encoded at 75 comes out *larger* than it went in, and slightly worse — because the encoder is now faithfully preserving the compression artefacts of the first pass. That is the worst of both outcomes, and a tool that reports it as a success is lying to you.

So every result is measured against what arrived, and when the compressed version is not smaller you get the original back. The file is unchanged, which is the honest answer to "make this smaller" when it already is. Lowering the quality setting will still shrink it, at a visible cost you can then judge for yourself.

How to compress a JPG

  1. Drop your JPG onto this page, or click to choose one.
  2. It is compressed in your browser at the quality shown, with nothing uploaded.
  3. Check the saving. Adjust the quality or the size and convert again if you want more.

Compressing JPG: common questions

Does compressing a JPG lose quality?

Yes, by definition — JPEG is a lossy format and compressing it means keeping less. The useful question is whether the loss is visible, and at quality 75 on a photograph it usually is not: the detail being discarded is the fine texture your eye was not resolving anyway. Below about 60 it starts to show, first as blotchiness in smooth areas like skin and sky.

Is my photo uploaded?

No. The JPG is decoded and re-encoded inside your browser, so the file never leaves your device. You can check: open the network tab of your developer tools and compress something — you will see the page and the advertising this site is paid for with, and nothing carrying your photograph.

Why did the file get bigger?

It should not have, and it will not here. If the compressed version comes out larger than the original — which happens when the file was already saved at a low quality — we return the original untouched instead. Other tools hand you the larger file and call it compressed.

How small can I make it?

Far smaller than most people expect, but the honest limit depends on the picture. A detailed photograph at quality 40 is visibly degraded; a simple one with flat backgrounds survives it easily. If you need a specific number, use the target size pages — they encode at several qualities and keep the best one that fits, rather than making you guess.

Is there a limit on how many I can do?

There is no account and no watermark. The free tier takes files up to 100 MB and a hundred at a time, which a JPG reaches only if it came off a scanner — below that the limit is your patience and your device, because the work happens on your own machine.

Sometimes the better answer is a different format — especially for a photograph stored as JPG.