How to Convert Multiple FIT Images to JXL?
1. Download and Install reaConverter
First, grab reaConverter from the download button below. Installation is fast, and the software runs offline — no account or signup needed. reaConverter also includes editing tools: resize, crop, rotate, and more.
2. Load your FIT files
Open reaConverter and add your FIT files. You can load individual files, entire folders, or even nested subfolders.
Drop your FIT files into the window or use File menu to browse and select folders.
3. Select JXL as output format
Choose JXL as the target format. Pick a destination folder or let reaConverter save files alongside the originals.
4. Start FIT to JXL conversion
Hit Convert and let reaConverter do the work. The progress window shows status for each file in real time.
After conversion, find your JXL files in the output folder. Click 'Show converted files' to open it directly.
How FIT and JXL differ in practice
FIT stores 32-bit greyscale covering the full dynamic range of the scan, and JXL shows 8 bits. The conversion applies a window level, so what ends up visible depends on the window you choose. Decide separately whether patient metadata should be copied to the output or stripped from it. FIT stores pixels without compression loss and JXL does not, so this is a one-way step. Choose a high quality setting, and avoid converting the same file back and forth, because each pass compounds the artefacts.
