I called T-Mobile an a representative told me that there were two ways of sending an MMS, specifically a picture, with the Moto X:
1. Stock Messaging App > Thread > Attach(Paper Clip icon) > Pictures. Then you select a picture from your gallery
2. Stock Messaging App > Thread > Attach(Paper Clip icon) > Capture Picture.
With the representative on the line, we tried both ways and figured out that option 1. works while 2. does not.
The conclusion that we came to is that if you capture a picture immediately, then it takes a full size picture and DOES NOT re-size it for MMS at all. HOWEVER, if you take a picture beforehand and then add it to a message from the gallery, it DOES re-size it.
I plan to call Motorola tomorrow and tell them about this issue so that hopefully they can either send out a fix or add it to an overall OTA update.
Hopefully I can contribute something to this forum haha