Why do some contacts on the favorites screen on Phone.app show initials and others an icon? In iOS 7 the contacts in my favorites screen in Phone.app that don't have a photo show either initials or a person icon. Why not just one or the other and what determines which image a contact will get?

I think this is best shown with a picture:
The icon is displaying because that contact's "name" is entered as a business name, and their "First" and "Last" names are blank.