Have you noticed that some of your contact photos show up full screen when a contact calls you, while other contact's pictures only show up in the top right of the display? It's a weird behavior that has frustrated many iPhone users.

It appears that if you select the photo for the contact by editing the address book entry on the iPhone, the picture shows full screen. If you instead edit the entry on your computer and then sync it to your phone you get the small photo.

Here's a tip. Create an album of all your contact photos in iPhoto and sync it to your phone. Then go in and select contact photos for your favorite contacts on the iPhone. You'll have full sized, full screen photos for your favorite callers.