there is a certain size limit for MMS in kilobytes. so a huge 2MP picture at full resolution, will get shrunk down to fit in the limitations of one MMS. i forget how big it is though. usually only 160 x something else. i think 300 kB is the current recommended size used by networks due to some limitations on the WAP gateway side.
If the intent is that the recipient view the image on their phone, 2MP would be major overkill. If you want them to have the full image, I think your only option is e-mail.