While working on a major update for Diary I was searching for a solution to display the users Address Book picture until I realized that there are a lot of people out there not using it or don’t have assigned one.
But every one has a login picture - even if it is the random default one. And there actually is a way to query it:
CBIdentity *identity = [CBIdentity identityWithName:NSUserName() authority:[CBIdentityAuthority defaultIdentityAuthority]];
[identityView setImage: [identity image]];
// don't forget to include the Collaboration framework
