I need software (free or paid) to undelete (recover) lots of ~4 MiB JPEG files from a heavily fragmented FAT32 filesystem. I need the full JPEG files, not only the first cluster (4 KiB). The JPEG files were not contiguous on disk, they were heavily fragmented (up to thousand fragments per file). The filesystem is indeed FAT32. The device is healthy, there are no I/O errors. Some of the files alhave been partially overwritten since the deletion, I don't need those.
I need software which knows the JPEG file format very well, and it can autodetect, sort out and glue together JPEG files from thousands of fragments (in unspecified order). I'm only interested in recommendations for which the recommender knows for sure about this feature (autodetecting and gluing together JPEG file fragments).
I need software which works out of the box, and which I (as a motivated power user) can download and run. I have Windows and Linux, I'm sufficiently familiar with both.