JPEG XL is the modern successor to JPG. At the same visual quality a JXL file is usually 20–60% smaller, and it supports HDR, wide colour, transparency and true lossless compression. That makes it a good choice for archiving photo libraries or serving images on a website that has a JPG fallback.
Safari on Mac, iPhone and iPad has opened JXL files since 2023. Chrome and Firefox only began switching JPEG XL on by default in their autumn 2026 releases, so people on older browser versions, many apps and most upload forms still cannot open them. Keep your original JPGs if you need to share the photos widely.
Encoding runs on your device with a WebAssembly build of the reference libjxl encoder. The first file takes a moment while the encoder (about 1.4 MB) loads, and very large photos can take several seconds each.
How to use it
- Choose one or more JPG files.
- They convert to JXL automatically. Adjust the quality if you like.
- Download each file, or all of them as a ZIP.
Questions
What quality should I choose for JXL?
Around 80% looks the same as a high-quality JPG for most photos. Set 100% for mathematically lossless output, which is larger but keeps every pixel of the decoded JPG.
Can I open JXL files on Windows?
Windows 11 can view JXL with the JPEG XL Image Extension from the Microsoft Store, and current Chrome, Edge and Firefox versions open it too. If someone cannot open your file, send the JPG instead or convert it back with the JXL to JPG tool.
Does this re-compress the JPG?
Yes. The JPG is decoded to pixels and encoded again as JXL, so it is not the bit-exact "JPEG recompression" mode of the command-line tool. Use 100% if you want no further loss.
Are my files uploaded to a server?
No. The tool runs entirely in your browser using JavaScript, so your files never leave your device. You can even disconnect from the internet after the page loads and it keeps working.
Is it free?
Yes, free with no sign-up, no watermark and no daily limit.