If you ask me, the facial structure and body type look too young to be Babs. It's not really a "Babs" smile either. The boobs are much too big to be Cass though. My bet would be on Steph--the smirk fits her, and the backround is purple. She's young enough, and Robin did forbid her to be Spoiler (which is all bullshit anyway, but whatever)...but not Batgirl.