katlab tools/compress

Compress Images · JPG, PNG & WebP

Shrink image file size by quality or a target size — all in your browser.

Images are processed locally. Nothing is uploaded to a server.
0 images

How to compress an image online (free)

  1. Drop your images onto the box above, or click to choose them.
  2. Pick an output format and either drag the Quality slider or set a target size in KB.
  3. Click Compress, then download each result or use Download all.

Quality slider vs. target size

The quality slider gives you direct control — lower quality means smaller files. Target size is easier when you have a hard limit (say a 200 KB upload cap): the tool re-encodes the image a few times to find the highest quality that still fits under your number. If you set a target size it takes priority over the slider.

Which format compresses best?

WebP almost always produces the smallest file at a given quality and supports transparency, so it's the default here. JPG is the safest choice for maximum compatibility with older software. Choosing Keep original re-encodes each image in its own format — useful when you must stay PNG or JPG, though PNG is lossless and won't shrink as much.

Why katlab's image compressor is different

Most "compress image" sites upload your pictures to their servers. This one doesn't. The compression happens inside your browser tab using the HTML canvas, so your images never touch the network — nothing to leak, cache, or delete later.

Is it really private?

Yes. There is no upload step and no account. You can open your browser's network tab and watch: no request carries your image data. The tool works offline once the page has loaded.

Will compressing reduce quality?

Compressing to JPG or WebP is lossy, so some detail is traded for a smaller file — that's the point. Keep your originals if you might need full quality later, since compression cannot be undone.