The royalty-free successor to JPEG — smaller files, lossless recompression of old JPEGs, and support that's still catching up across apps.
JPEG XL (file extension .jxl) is a royalty-free image format designed by the same standards body behind the original JPEG, built to replace it rather than extend it. It compresses better than classic JPEG at equal quality, supports transparency and animation the way WebP and AVIF do, and includes a feature neither of those formats has: it can losslessly repackage an existing JPEG into a JXL file that is smaller but can be converted back to the exact original JPEG bytes. Despite that pedigree, JXL adoption has been slower and more contested than WebP or AVIF — Chrome shipped support, then removed it, and as of this writing Safari and iOS support decoding and encoding JXL starting with iOS 18, while most of Android, Windows, and older software still do not recognize the format at all. A JXL file that arrives from a photography app or an experimental camera setting is far more likely to need converting than to open on the next device it reaches.
iPhone and iPad on iOS 18 or later, and recent Mac software, decode JXL natively. Everywhere else — most of Android, Windows outside specialist viewers, and any device on an older OS — a .jxl file typically will not open at all.
Outside of iOS 18 and later and a handful of specialist photo tools, almost nothing opens a JXL file yet. Converting it to JPEG or PNG on-device turns an unrecognized file into one every app, printer, and upload form already understands.
Filemorph can convert JXL to PNG on-device — lossless output that opens on every device, including ones without JXL support.
Filemorph converts .jxl files entirely on-device on iPhone, iPad and Mac — no upload, no account, and it works in Airplane Mode.
Relevant operations in Filemorph:
No, despite the similar name. JPEG 2000 (.jp2) is an older wavelet-based format mostly used in medical and satellite imaging. JPEG XL (.jxl) is a newer, unrelated format aimed at replacing everyday JPEG photos with smaller files and better quality.
JPEG XL support is still rolling out. Filemorph can decode and convert a .jxl file on iPhones and iPads running iOS 18 or later; on an older iOS version, in most Android browsers, or in most desktop software, the format is not recognized yet.
No. Filemorph converts JXL to PNG or JPEG entirely on-device on a supported iPhone or iPad, so the image is never uploaded anywhere, and the conversion runs the same with no connection at all.