How do you send pictures messages on iphone with AT and T?

Start by making a picture message only instead of sending it to a number send it to an e-mail. I'm not sure how to do it on all phones but normally when you go into the part where you pick who you want to send it to there's an option that says [New E-mail Address] or you can go into your Contacts and add a new contact and instead of a number use an e-mail.