How do I change my profile picture in the lock screen? Not the background but the little picture.

it works just go to system prefrences at the top left corner of your screen there should be a little black apple click on that then go to system prefrences then click on the icon users and group then click edit

System preferences -> System -> Users & Groups....click on your account -> draw a new picture onto your existing one ...done

Hope this helps

How to:

http://support.apple.com/kb/PH11469

Hope this helps.