How can I adjust picture file?

MMS size limit is determined by the carriers, not Apple. That's why there is no setting on the iPhone to do so as the carriers automatically re-size the pic to conform with their network standards.

actually it does answer your question. YOU CANT the carrier does it plain and simple. Unless you want to take it off the phone to a computer and downsize it in photoshop then bring it back to your phone to send out.

Message was edited by: sn4p2k