Compress Images Online

How it works

1. Drop in JPG, PNG, WebP or HEIC files, as many as you like.
2. Choose a quality. Around 80% is usually indistinguishable from the original.
3. Leave the format on Auto and each image is encoded every way and kept at whichever came out smallest.
4. Check the saving on each row, then download.

About this tool

Shrink JPG, PNG and WebP files so they fit an upload limit or load faster on a website, with a quality slider and a live preview of the size you will actually get. Runs entirely in your browser, so nothing is uploaded.

Before picking a number: what compression actually throws away explains why 80% is not 80% of the quality, and why resizing before compressing gets you a much better-looking file at the same size.

How much quality can I lose before it shows?

For photographs, 80% is the usual sweet spot: files land at roughly a fifth of their original size and the difference is invisible at normal viewing size. Below about 60% you start to see blocking in smooth areas like skies and skin. Screenshots and images with flat colour or text behave differently, they suffer badly under JPEG at any quality, and are far better served by WebP or PNG, which is exactly what Auto is for.

Why does Auto sometimes pick a different format?

Because guessing from the input format gets it wrong often enough to matter. A PNG screenshot can shrink by 90% as WebP, while a photograph that arrived as PNG is usually smallest as JPEG. Rather than assume, the tool encodes your image every way your browser supports and keeps whichever file came out smallest. That costs a moment of processing on your own machine and nothing else.

Does compressing twice make it smaller again?

No. It makes it worse. JPEG and WebP are lossy, so each pass throws away detail that cannot come back, and re-compressing an already-compressed file mostly adds artefacts rather than saving space. Always compress once, from the original.

Quality, or a size to hit?

Two different jobs, and the panel does both. Setting a quality is the right move when you want the file smaller and nobody has given you a number: pick 80%, look at the saving, and stop. Setting a target size is right when a form, a mail server or a content system has handed you a limit, because then the quality is not a decision you should be making at all — the tool searches for the highest setting that clears the limit, which is a better answer than any number you would have guessed. If you arrived holding a number, the pages for 100 KB, 200 KB and 500 KB open with it already set. A JPG or PNG that has to stay one gets there differently, and each has its own page: a JPG under 100 KB, a JPG under 50 KB, a PNG under 100 KB and a PNG under 50 KB.

Why nothing happened to one of my files

Because the tool could not beat it, and handing back a larger file while calling it compressed would be a lie. An image that was already exported efficiently — a small PNG logo, a JPEG somebody has been through once already — comes out of every encoder larger than it went in, so the original is returned unchanged and the tile reports the same size twice. That is the correct outcome, and it has one consequence worth knowing: a file that was handed back untouched still carries whatever metadata it arrived with, because nothing was re-encoded. If stripping the location off a photograph was the actual point, use Clean, which does it without going near a pixel.

Resize first, then compress

The single biggest improvement available on this page, and it is not a setting. A 4000-pixel photograph squeezed to 200 KB forces the encoder to destroy detail across twelve million pixels, and the result looks mushy everywhere. The same photograph resized to the 1200 pixels it will actually be displayed at, and then compressed to 200 KB, spends the same budget on a tenth as many pixels and looks sharp. Compression decides how much each pixel costs; resizing decides how many you are paying for, and the second question is usually the one worth asking first.

Starting from a format you already have

The format decides what compressing can and cannot do, so each one has a page that says so plainly: JPG, where the quality slider does the work and compressing twice is the trap; PNG, which is lossless and has no quality to lower at all; WebP, which comes in a lossy and a lossless form sharing one extension; and PDF, where making the file smaller means turning the pages into pictures and losing the text.

Nothing here leaves your device

Every encode happens in this browser tab, on your own processor, which is why there is no upload bar and no limit on how many files you can drop at once. It is also why the tool can tell you it tried four encoders and kept the smallest: on a server, that would be four times the bill. Here it is a second of your own machine's time and nothing else, and the picture never exists anywhere but on the device you are reading this on.