I'm no developer, I'm no programmer -- but I have thought about this before.
So here is my idea.
A program that is made could simply use my main email address and send it to every single MMS carrier email. The idea being, that it would only go through to the correct one, and the wrong carrier emails would just not show up anywhere.
I am sure options could be added, to where you could click send and it would just open that program, you enter the number and it sends it to all [how many ever MMS carrier email addresses there are] addresses.
I can't attest to being the most clear writer as sometimes my thoughts get ahead of my typing, so here would be a walk through of how I picture it.
I snap a picture of a hilarious squirrel. I proceed to clicking 'send', left soft key, and it pulls up this new mysterious program. I push a button, choose my contact, and proceed. I am not in the mood to add a subject, so I just click "send" - and the program prepares an email to:
1234567890@message.alltel.com,
1234567890@mobile.mycingular.com,
1234567890@messaging.nextel.com,
1234567890@messaging.sprintpcs.com,
1234567890@tms.suncom.com,
1234567890@tmomail.net,
1234567890@voicestream.net,
1234567890@vzwpix.com,
1234567890@mms.uscc.net ,
1234567890@mms.mycricket.com
all at once, and the rest will just float off and reach no one in their servers, but the last one will reach someone. And so they have received their picture, albeit not from my phone number but, personally I don't mind if they see "from:
myname@gmail.com" --> they know its me, and they can reply.
Does this sound reasonable?