This is a brief paper that describes how sending external email to an account automatically maps things like a graphic if a person's personal email address maps to it. We tested this and it does work, but Facebook does add a little icon saying the sender isn't verified. However, the average user will probably overlook this.
5b503a91fa75c821b880ed02d9f1bfcea98221c81d919e117cbfcd16eade343f