Yeah, I think they needed to include something from the prequels but it just goes to show how much the PT effed up that they couldn't include a good looking pic of the Emperor from ROTS (I will never understand how they messed him up so badly).
Looking again I think the Vader they used is from ROTS too but I don't mind that nearly as much.
I'm surprised and really happy they didn't use PT Yoda, which I had expected.