I actually just tested this out on my phone and the mms came through. I am using an iOS device so it might be a little different. What options do you have when opening the message? Is there a download option? Can you also try taking a picture on your phone and sending it to your own phone number via regular MMS and let me know if it comes through?
Chris, I called T-Mobile phone support and was supposed to be escalated to get an answer. But I was disconnected and the second agent I spoke with would not escalate the issue so I could speak with a supervisor. I was told that T-Mobile is blocking incoming text messages from all email addresses other than the major providers like Gmail, Yahoo, Hotmail, etc. That didn't make sense to me, so I asked again to speak to a supervisor and was denied.
I did some research online here and found that the APN address in my T-Mobile issued phone was different than one listed for correcting this problem on unlocked phones. So, I created a new APN connection and changed the APN type to: default,mms,supl,hipri,admin,mobile. I saved the new APN listing, powered off my phone, restarted and tried to send an MMS message from my computer to my phone. This time, the photo appeared in my phone's messages just fine except that there was also coding from my original message which appears to be coding from the file itself. Still, I can view the image properly. So, I then sent a photo from Messaging to my computer email address and the message went through just fine. So, I seem to be on the right track. Now I just need to figure out how to keep the photo file intact without it opening and displaying code.
Also, other than the message stating "Additional media content is included. Please check the message in detail," there were no options. There was no download box or other option. The Sender and Subject were there but the text of the message also was missing.