Having a picture of yourself as your phone's lock screen enables people in a shared location to look for you if you
lose your phone. (Of coure, if you're Jewish, or some other identity people dislike, this can potentially backfire.)
On that note, you can rename your USB drives, mp3 players, etc., with your phone number, and you
can put a .txt file on them named "IF YOU'VE FOUND THIS USB, please return it to [contact info]."