JPG to JXL Converter
Losslessly recompress JPEG files as JPEG XL with original-JPEG reconstruction data, or choose an explicit new JPEG XL encode.
Reconstruction is not re-encoding
A JPEG-derived JXL can store the original JPEG structure. Reconstruction restores those exact original bytes. A new JPG encode decodes pixels and compresses them again, so its bytes and pixels may differ.
Format limits stay explicit
PNG and JPG cannot represent every JPEG XL HDR signal, extra channel, animation feature, or metadata box. Animated JXL is never sent to JPG, and animated PNG output uses APNG so frames are not silently discarded.