Everything points to the fact that jpeg to xpm conversion almost certainly searched by users that are looking for a software that can be used to turn standard JPEG images to XPM format, most likely to use these files on old machines/servers or virtual machines running X Windows system.
You can actually still find graphics editor that support XPM format, there are not many, but they do exist. For example the free GIMP.
Updated: October 13, 2023