Yes, i'm hearing that this does not work, for several other people here.
I don't know what to tell you..... try to have someone send you an MMS and an Email with picture attachment from their phone.
See which one works.
If the MMS message comes to you with the picture, then check the return address on it, and see how it's formatted. If the email works, then there's your solution.
I had been told that you can only send and receive pictures on the iPhone via email, NOT TEXT. Which bites as I have always been able to send and receive pictures via text, phone to phone, this seems pretty basic to me. If someone knows different, please let me know.