I work with a local maker space teaching 3D printing, a few months ago i was give a RPI as a gift and as i have been learning about all it can do. After seeing my RPI in action Vocademy (maker space in Riverside, Ca) asked if it could be used for slide shows and to post other information on the big screen. I know that XBMC can be used for slideshows but locking for something simpler. this RPI is meant to be mounted to the wall and not moved and have no keyboard or mouse plugged in or pc remote even. i want to ssh in so that in future the slideshow can be updated or i can even write a scripted that download new pictures for me.
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
Next i found this build of Raspbain that is a digital sign that i really though would do the the trick. however there is both a paid version and a free version and the free version is very limited in what it can do so this is also a no go http://www.binaryemotions.com/raspberry-digital-signage/faq.html