Here goes! When I send text messages my profile doesn't show up. It ays "the contact doesn't exist" I've checked all my pic areas and I just can't get it restored.
Go to apps then people and under your name edit from there. You may have to long press on the blank pic part, I forget, but that's where you do it. Hope that helps.
Make certain your own entry in People actually has your mobile phone number listed. You should appear at the very top of the People list under the heading "Me" - that is the entry used by the Messaging app (as far as I can tell...).