i am currently use Gimp 2.6.4 on Window XP packe2. We have made a path in images and save as in format JPEG and then reopen this picture again but no path.
If possible Gimp software is save path in these format and reopen have path.
IIRC some work has been done to read and save the crop path in TIFF files.
For JPEG and EPS, you should have a look into the file-jpeg and file-ps plug-ins and check if you can contribute to them.
I'm doubtful about loading paths from EPS as long as ghostscript is used to render it, however (maybe this will become better with libspectre.