I just wanted to throw out there that the source of the images that are currently used does have the images for cards from a specific set, if present.
http://www.wizards.com/global/images/magic/MOR/Boldwyr_Intimidator.jpg
vs.
http://www.wizards.com/global/images/magic/FUT/Boldwyr_Intimidator.jpg
I know that it's not that big a deal to alot of players, but I like to use cards from different sets just to mess with people's heads.