no send mms on iphone 4s since ios7

If you go to Settings>Messages>is MMS Messaging on? If it is and you are not able to send an MMS, then try going to Settings>General>Reset>Reset All Settings. This will not affect your data, just settings and passwords. If that does not work, you can next try Reset Network Settings. If neither of these restore the function, then I would contact your carrier. MMS Messages are a carrier function and if resetting the phone has not corrected it, then there is something wrong on the carrier end. The switch that I described is the only setting there is for MMS on the iPhone.

MMS is not iMessage.

There's SMS (text message), MMS (multimedia, like photos/videos) and iMessage.

SMS & MMS are controlled by the carrier exclusively. iMessage is an Apple-only service.