We had a nice photo taken with Mr and Mrs Claus in Epcot, also Santa was at Downtown Disney but the photo there was very small (5x7 but most of it was Disney decoration, my kids were tiny in the middle).
Another optoin is in the photo shops in any of the parks, they have a blue screen studio, you can have a family photo taken in there and they can add any background that you like, they have some nice ones with the castle and characters.
Bev