Disable send as picture message?

[MasterHowl]

Hello,

When I try to send a photograph via iMessage, it sometimes fails and sends it as a picture message...

This is running up my monthly bill, as I don't have picture messages on my contract. Is there any way to disable it?

Thanks!

 

[Gav2k]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)

Turn mms off

 

[MasterHowl]

Thank you!