ok i found this=you can change the picture size for multimedia messages (MMS) in the settings of your iPhone.
Under "General", "Network", "Cellular Data Network" and "MMS Max Message Size" you can set the picture size.
Please notice: usually your network operator is responsible for this settings and can change every multimedia messege for work with every phone in their network. ok i tried it and it works tmobile had it set to 1048756 i change it to 640480 hope it helps others