I've seen the two-part pour-on epoxy stuff before. Although that would be ideal for more dimensional items (doing up a map with all the State quarters would be cool!), the decoupage approach is more along the lines of what I was thinking of (I wouldn't have attempted spelling it though.. sheesh!).
Right now I've got a test board sitting outside in my baby toy hauler. I'm in the middle of putting the polyurethane on the walls (covered the interior with 1/4" luan) so it's easy to run the tests without using extra brushes. I'm testing out prints made with run-of-the-mill printer paper as well as one done on ink-jet photo paper. I'll get a coat or two of the poly onto it and report back on how they look.
Initial gluing of the photos was done with watered down white glue (although one piece of paper I put down with spray glue), allowed to dry overnight and then laid down a coat of polyurethane the next day.
Although it doesn't allow for a very precise cut - one approach that worked nicely was to rip the picture out by hand (normal paper only) leaving a tapered and frayed edge. Highlights around the picture and avoids a harsh edge which would take a lot of layers of polyurethane to smooth down.
Initially I figured on cutting out photos of motorcycles from magazines - but my daughter has lobbied heavily for family photos instead.