The comps are set 720×480 square pixel, the usual size for digital camera photos outputed to a fullscreen dvd. You can reset project for Blueray HD if you want at 1920×1080.
Simply bicubic resize in photoshop to 720×480 square. If you keep the loopout in precomp pictures, it will use that for the source of all rings continuously updated. Lay pictures down one after another, or export them from premiere as an avi slideshow. Scrub precomp pictures composition to see how it works.
If you don’t want the 3 rings to have the same source, duplicate precomp pictures, rename it, place it in a ring comp and copy/paste transform and parent information for each new pedal/precomp.