Traditional online converters
Many online tools upload your file to their server, process it and send the result back. That is slow (especially for large files) and means your personal images travel to a third party’s server.
The in-browser approach
On this site, encoders such as MozJPEG, WebP, AVIF and oxipng are downloaded to your browser as compiled WebAssembly (once, then cached). Your files are only read in browser memory and processed in parallel in Web Workers. Network traffic carries no file contents during conversion.
What is sent to the server?
Only anonymous usage counters: source/target format, byte sizes, duration and error type. File names, file contents and EXIF data are never sent. See the Privacy Policy for details.
Why strip EXIF?
Phone photos can carry the shooting location (GPS), date and device model. Removing this data before sharing an image publicly is a good privacy habit. The tools here always strip metadata from the output.
Limits
Browser processing is limited by your device’s memory and processor; very large images (tens of megapixels) can be slow on older phones.