Image Compressor — Free Tool
Shrink a JPG, PNG or WebP in your browser. Pick JPEG or WebP output, set the quality and an optional max width, and see the real before-and-after file size with the exact percentage saved. Nothing is uploaded.
Features
- Real byte sizes measured from the encoded file, never an estimate
- Quality slider from 10 to 100 with an optional max width for bigger savings
- Says plainly when re-encoding makes the file larger instead of hiding it
- JPEG or WebP output, with a warning before transparency is lost to JPEG
- Runs entirely on canvas in your browser — no upload, no account, no queue
Frequently asked questions
Why did compressing make my file BIGGER?
Because it was already compressed. A JPEG or WebP that came out of a phone, an export preset or another compressor has already thrown away detail and left behind its own artefacts. When you re-encode it, the new encoder cannot tell an artefact from real detail, so it spends bits faithfully reproducing the noise the previous one added — and at quality 80 or above that often costs more bits than the original file used. The tool reports this instead of showing a negative saving as if it were a win. Drop the quality, set a max width, or keep your original.
What quality should I pick?
70 to 85 is the usual range for photographs: the file shrinks a lot and the difference is hard to see at normal viewing size. Below 60 you will start to notice blocking in skies and smooth gradients. Above 90 the file grows quickly for very little visible gain.
Should I use JPEG or WebP?
WebP is typically 20–30% smaller than JPEG at the same visual quality and every current browser supports it, so it is the better choice for the web. Stick with JPEG when the file has to go somewhere with older tooling — some CMSes, email clients and desktop apps still refuse WebP.
Why does setting a max width save so much more than the quality slider?
File size scales with pixel count. Halving the width also halves the height, so you are encoding a quarter of the pixels. A 4000px phone photo displayed in a 1200px column is carrying more than ten times the data anyone will ever see — resizing it is almost always the biggest single saving available.
Are my images uploaded anywhere?
No. The file is read by your browser, decoded into a canvas and re-encoded there. It never leaves your device, no request goes to any server, and there is no account to create.
