Image Compressor
Shrink and resize images in your browser, with the result weighed as you go.
Part of image tools and design tools.
Resize first, then compress
There are only two ways to make an image lighter and they are not equally effective. Resizing removes pixels outright, and it is almost always the bigger win: a photo 4000 pixels wide displayed in an 800-pixel column is carrying twenty-five times more data than the screen can use, and no amount of quality tuning will fix that. Lowering the quality keeps every pixel and discards detail within them. Do the resize first, then bring the quality down only as far as it still looks right, and most images land under an upload limit with nothing visibly lost.
Hitting a specific file size
Quality and file size are related but not predictable: the same 80% setting produces wildly different sizes on a flat graphic and on a detailed photograph, so there is no formula that turns “200 kB” into a quality number. The target-size mode instead encodes the image several times, narrowing in on the highest quality that still fits, and hands you that one. If even the lowest quality overshoots, it says so rather than giving you a file that misses the limit — at that point the dimensions are what need to come down.
Compression is one-way
Every lossy save discards information permanently, and re-saving an already compressed image compounds it — the artefacts from the first pass become detail the second pass faithfully tries to preserve. Always work from the largest, least-processed original you have rather than from a copy that has been through a messaging app. For the same reason, compressing an image twice at 80% is worse than compressing it once at 65%, even though the second sounds more aggressive.
Nothing is uploaded
The image is decoded, redrawn at the size you choose and re-encoded entirely inside this page, using the canvas APIs the browser already provides. No copy is sent anywhere, which is the difference that matters when the file is a scanned document, an identity paper or a photograph of someone who did not agree to it being on a stranger’s server. Disconnect from the network and the tool keeps working, which is the only demonstration of that claim worth trusting.