my next test in the Rasberry pi slide show is this build of Raspbain 

http://www.screenlyapp.com/

I am testing the open sources version but once again this means we need to have a network connection in the room i like this one the best so far because i can add more images and can likely build a scripted to update the images but will need to wait until im sure that the network is up and running in the room. I am using the open sources version because I don't want to have to use the web version 

http://www.screenlyapp.com/ose.html