Does compressing change the image's dimensions?

No, the width and height stay the same. Only the amount of detail stored changes. If you want fewer pixels, use the Image Resizer, which is often the more effective way to get a much smaller file.

Why can't it always hit my target size?

Quality has a floor, and a big detailed photograph can still be over a small target at that floor. Resize it first and the target becomes reachable.

Is quality 75 the same everywhere?

Roughly, but not exactly. The number goes to the browser's own encoder, and encoders differ a little between browsers, so the same setting can give slightly different sizes on different devices.

Are my photos uploaded?

No. Decoding and encoding both happen in your browser. Nothing leaves your device, which is also why there's no account and no queue.

Image Compressor

Make a photo smaller, either by picking a quality or by naming a file size you have to come in under. Useful when a form won't accept anything over 200 KB and gives you no help getting there.

Choose an image or drop it hereJPG, PNG or WebP, up to 50 MB.

Runs entirely in your browser. Your files are never uploaded.

How to use Image Compressor

1Pick an image, or drag it onto the box above.
2Choose a quality, or switch to aiming at a file size in kilobytes.
3Pick an output format, or keep the one you started with.
4Press Compress image and download it.

Picking a quality versus naming a size

Choosing a quality is the normal way to do this. The number controls how much detail the encoder is allowed to throw away, and about 75 is where most photographs stop looking any different at normal viewing size. Push it low and you'll see blocking in smooth areas, skies especially.

Aiming at a file size is for when somebody else set the rule. A government form that refuses anything over 200 KB. A forum with a 500 KB cap. There's no formula that turns a desired size into a quality number, because it depends entirely on the picture, so the tool encodes the image several times at different qualities and keeps the highest one that fits. That's why this mode takes a couple of seconds longer than the other one.

If even the lowest quality can't get under your target, you get told, rather than quietly handed a file that misses it. At that point the answer is almost always fewer pixels: a 4000-pixel-wide photo has four times the data of a 2000-pixel one, and no amount of compression argues with that.

Which format to compress to

Keeping the original format is the safe answer. WebP is usually smallest for the same visual quality, often by a quarter or more against JPG, and every current browser shows it, though some older desktop software still won't open it.

PNG is lossless, so the quality slider does nothing at all to it. Compress a photograph to PNG and you'll typically end up with a bigger file than you started with. PNG earns its keep on screenshots, diagrams, anything with sharp edges or transparency.

What happens to the original, and to the metadata

Nothing happens to the original. The file on your device is untouched. The tool decodes a copy in memory, re-encodes it, and hands you a new file.

Compression is lossy, so avoid compressing an already-compressed image over and over. Each pass throws away a little more and the damage builds up. Work from the original every time.

Metadata doesn't come across. The re-encoded image has no EXIF block, which means camera model, timestamp and any GPS coordinates are gone. Usually that's exactly what you want before posting a photo publicly, but if you're archiving family photos and want the dates kept, this is the wrong tool.

Limits

50 MB per image.
Very large images are limited by your device's memory, since the decoding happens in your browser.
EXIF metadata, GPS coordinates included, is not preserved.
Animated GIFs aren't supported. Only the first frame would survive.

Frequently asked questions

Does compressing change the image's dimensions?: No, the width and height stay the same. Only the amount of detail stored changes. If you want fewer pixels, use the Image Resizer, which is often the more effective way to get a much smaller file.
Why can't it always hit my target size?: Quality has a floor, and a big detailed photograph can still be over a small target at that floor. Resize it first and the target becomes reachable.
Is quality 75 the same everywhere?: Roughly, but not exactly. The number goes to the browser's own encoder, and encoders differ a little between browsers, so the same setting can give slightly different sizes on different devices.
Are my photos uploaded?: No. Decoding and encoding both happen in your browser. Nothing leaves your device, which is also why there's no account and no queue.