Is this image compressor really free?

Yes. Image Tools is completely free with no account, no subscription, no watermark and no daily limit. You can compress and convert as many images as you like, in any supported format, at any quality setting.

Are my images uploaded to a server?

No. All compression happens locally in your browser using WebAssembly versions of MozJPEG, libavif, libjxl, libwebp and OxiPNG. Your files never leave your device, are never stored and are never seen by anyone else — so the tool is safe for confidential documents and personal photos.

Which image format gives the smallest file size?

AVIF is usually the smallest, typically 40–60% lighter than an equivalent JPEG. JPEG XL is comparable but has limited browser support. WebP is the best all-round choice when you need both small files and universal compatibility.

How much can I compress an image without visible quality loss?

For most photos, a quality setting of 75–80% removes 60–90% of the file size with no difference visible at normal viewing size. Screenshots and graphics with flat colour and text usually look better in PNG or at a higher quality value.

Is there a limit on file size or the number of images?

There is no server-side limit because nothing is uploaded. The practical limit is your device's memory. Files are processed three at a time so that even a batch of several hundred images stays responsive.

Can I convert between formats, for example PNG to WebP?

Yes. Any supported input (JPEG, PNG, WebP, AVIF, JXL) can be converted to any supported output (AVIF, JPEG, JPEG XL, PNG, WebP). Just pick the output format before dropping your files in.

Does it work on a phone or tablet?

Yes. The tool works in any modern mobile browser, including Safari on iPhone and Chrome on Android. Very large images take longer on a phone because compression uses your device's own processor.

Does it work offline?

Once the page has loaded, compression itself needs no network connection at all, because the codecs are already running on your device.

Free Image Compressor & Converter — AVIF, WebP, JPEG, PNG, JXL