I appreciate everyones posts here. I just got my 2010 Edge Sport last Wednesday and love it so far.
For my 2010 Edge Sport with SYNC and Nav I did some testing and I have found that 650 x 410 seems to be the perfect size. I guess that would be the Gen 1 systems where you can only have your pics on on side or the other of the screen. I still wish there was a way to set a default other than the Ford logo. Anyone figure out the randomize function? I can't seem to figure out when it changes the pictures yet.