What xs2k said actually works. Follow these directions. I know when you go to fill in the MMSC it will tell you that you have too many characters but thats fine. Just hit the ok button twice. Then the letter that you typed before will still be typed. You have to do this for all of the leftover letters.
1.Go to the Marketplace, tap “Samsung Zone”, and download “Wireless Manager”
2.Once that’s installed, open the Wireless Manager app
3. Go to the “apn” screen, and tap “edit apn”
4.Push the “+” button at the bottom
5. Fill out the data as follows: (any fields that I didn’t mention should be left at the defaults)
6. APN Name: MMS
7. Profile Category: MMS
8. MMSC:
http://mms.msg.eng.t-mobile.com/mms/wapenc
9. APN:wap.voicestream.com
10. Auth type: none
11. Proxy address:216.155.165.50
12. Proxy port:8080
13. Click the checkmark button on the toolbar
If for some reason this doesn't work you may have to manually put some other settings in if its an unlocked phone. Try going to your home page, then to settings, then to cellular. Under cellular make sure that your data connection is on and under "data roaming options" select roam. Then go to edit apn. If you have t-mobile the APN slot should read: epc.tmobile.com
If it doesn't then write that in. All other fields ( including username passworkd, proxy sevice/url, and proxy port) should be left blank. I'm not sure if this matters but it was also suggested to have your wifi turned off when sending a picture.
If for some reason this still doesn't work you may be missing another apn. I'm not actually sure if this does anything but I have it on my phone and its working. If your phone already works then I wouldn't worry about it. But if it doesn't then..
1. Go into wireless manager
2. Go to edit apn then hit the +
3. APN name: internet_line
4. Profile catagory: select internet (always on)
5. APN: pta
6. Auth type: none
7. Leave ALL other fields blank
8. Hit the checkmark
It will bring you back to your apn list. The apns that I have listed now are MMS, internet_line, and another APN that has a long list of letters (this is the result of going into settins-cellullar-edit apn ect. that you did earlier). I can't give you the exact list of letters because it is different per phone. ( but if you want to make sure that its the one I'm talking about you shouldn't be able to delete it if you try. It will say that you have to go to settings cellular and change it) Any other apns I have deleted. So you should have those three. Try sending a picture message and see if it worked out. This worked for both me and my sisters phones. We both have t-mobile and are using an unlocked AT&T samsung focus 2. Hope things work for you
This is all of the setting informationthat I know of that could help