How can I add missing avatar/profile pictures in Messages? In the new Messages application introduced with Mountain Lion, I cannot see my own avatar.

This is happening even though my Messages.app email is linked with my contact in Contacts.app.

No Avatar appears when I text in Messages:




But I do have an avatar in Contacts:
You can set your own avatar, one that is even different from the one in your address book with the following menu selection:

Messages &#x2192; Change my Picture...