🗜️ Compress Image
Drag in a photo, adjust the quality slider, and watch the file size shrink in real time — before you download.
About Compress Image
Compress Image reduces the file size of a JPG, PNG or WebP photo by re-encoding it at a lossy quality level, entirely inside your browser. It's the tool to reach for when a photo needs to fit an upload limit — an email attachment, a CMS media library, a form that caps files at a few megabytes — or when you want faster-loading images for a website without setting up a build pipeline.
The tool draws your image onto an HTML5 canvas element and re-encodes it using canvas.toBlob() with the quality value set by the slider. That quality parameter only affects JPEG and WebP encoding, controlling how aggressively the codec quantizes color and detail data — which is why PNG isn't offered as a compression output; PNG is lossless and has no equivalent quality setting. Because the encode happens in JavaScript on your device, the original file never leaves your computer.
Compression works best on photographs with natural color gradients — skies, skin tones, foliage — where the eye doesn't notice small losses. Screenshots, line art and text-heavy images tend to compress poorly and look blocky at lower settings, since JPEG's DCT-based compression wasn't designed for sharp edges. Also note that if your source image already has visible compression artifacts, re-compressing it won't recover the lost detail; you're always working from what's already there.
Frequently asked questions
Will compressing reduce visible quality?
At 70–90% quality most photos look virtually identical while shrinking significantly. Lower settings trade more visible quality for smaller files — the live preview shows you exactly what you'll get.
JPG or WebP — which should I choose?
WebP typically produces smaller files at the same visual quality, but JPG has universal compatibility with every app and website.
Does compressing to JPG remove transparency?
Yes — JPG has no alpha channel, so any transparent areas in a PNG source get filled with a solid background (typically white) once you choose JPG as the output. Pick WebP output instead if you need to keep transparency.
Why didn't the file size change much at 90-100% quality?
Very high quality settings keep almost all of the original detail, so the reduction is small. The bigger savings usually show up in the 60-85% range, where the encoder starts discarding data a viewer is unlikely to notice.
Is there a limit to how many images or how large a file I can compress?
No limit is enforced by the tool itself, since everything runs in your browser instead of being uploaded to a server — the practical ceiling is how much memory your device and browser tab can handle for a very large image.