... this program recommends using JPG as base and RAR as container, this program allows you to create any image-archive you like. (They may not work.) This program only allows you to extract RAR containers.
Technical details on JPGRAR: http://googlebordello.crushhumanity.org/jpgrar.html
If you really like JPGRAR program, please consider donating here http://www.misc314.com/blog/donation/