Reversible JPEG XL workflow

Convert JPEG to JPEG XL Losslessly on Mac

Image2JXL can use JPEG XL's reversible JPEG recompression for JPEG/JFIF input. The resulting JXL keeps the original JPEG codestream so a compatible reverse workflow can restore the JPEG.

Download Image2JXL for Mac

Why use Image2JXL for this workflow?

Use reversible JPEG recompression

Lossless JPEG mode stores the original JPEG codestream in JPEG XL instead of decoding and re-encoding the photograph as a new lossy image.

Convert files or folders

Add individual JPEG files or drag in folders, then follow conversion status for each item in the batch.

Keep conversion local

Image2JXL performs JPEG XL conversion on your Mac. Source files are not uploaded to a cloud converter.

How to convert on Mac

Install Image2JXL on a Mac running macOS 15.6 or later.
Add JPEG/JFIF files or a folder containing JPEG images.
Select the Lossless JPEG mode and review the destination settings.
Run the batch, then keep the original files until the restored-output workflow has been verified for your archive.

Important format details

Lossless JPEG mode is specific to JPEG input

Reversible JPEG recompression applies to JPEG/JFIF sources. Other supported image formats can use pixel-lossless encoding where available, but they do not gain byte-for-byte restoration of their original containers.

Restoration depends on the JXL source

A JXL can restore the original JPEG only when it was created with lossless JPEG transcoding and still contains the required reconstruction data.

Keep backups for archival workflows

Test conversion and restoration with representative files before replacing or reorganizing an important photo archive.

Frequently asked questions

Is JPEG to JPEG XL conversion really lossless?

For JPEG/JFIF input in Lossless JPEG mode, Image2JXL uses reversible JPEG recompression and preserves the original JPEG codestream for restoration.