I probably would not use the remote as a DVD cover display menu because you're going to wind up with a huge CIF file that may bog down the iPronto. If you are going to do it (anyway) I would snag images of the DVD covers off of the Internet, bring them into Adobe Photoshop and create thumbnails of the images. You'll be able to set the aspect ratio (display size) for the iPronto page and then place the thumb nails on it in some organized manner.
There are cheaper and less expensive image editors around but I use Adobe Photoshop and Illustrator for all graphical work. Try ZDnet.com, do a search in the Download section for image editors, convert. You’ll find free or cheap shareware solutions there.
Sounds like your project might get a little big. A more efficient (less frustrating) method may be to set up and use Windows Media Center or something similar.
If I've missed the mark and all you need is an image editor to convert the images then you should find a quick and easy solution at ZDnet.