This is another issue where it matters how you do something to make it work.
If, like me first time you add the picture to a contact from your photo library or camera roll, then when the person calls, or you call them, it gets displayed full screen. If you add the contact's image into the outlook contact, and then resync, you will then get the format shown on the tv ad both when you call and are called.
Not sure if it matters, but I resized my contact images to 96 x 96 pixels.
Hope this helps
Martin