Here's mkmms. It's a minimalistic application that allows you to create an MMS and attach ONLY 1 file which can be jpg, png, gif or txt (I hadn't tested anything beyond jpg).

Note that it's alpha quality.

There's also a parser that will print some info about any MMS passed as an argument but it's commented out.

Use it like this:
./mkmms /home/mohammed/me.jpg m-send-req.mms subject

It needs QtCore and only that.

Don't ask about the license. It uses some bits from Qt extended, some from mmsdec and some are my own but you should be OK if you assume GPL for now.