Ability to edit and customize avatars to pictures I choose
Choose photos you want to see for each of your contacts
Andy Wall commented
I do like how it uses the contacts from my address book, there's a consistency there that works for me. However I also liked how the integrations with services in iOS allowed me to select an avatar, especially in the work environment where Exchange contacts have no avatar but I may know then via LinkedIn and could use this image.
using the same picture is fine by me, but more controls are better. But please keep the avatar picture square. when it's rounded like in other apps, I simply hate it: it cuts out part of pictures I choose just for style... :-(
So, give us the choices !