Problems sending picture messages on iphone 5.

I have an unlocked AT&T iphone 5 and I was wondering if anyone is having problems sending pictures from the iphone?

1. Open the Settings app.
2. Go to General -> Cellular.
3. Make sure that:
   • Cellular Data is ON.
   • Data Roaming is ON.
   • You can set "Enable 3G" to ON if you are in a refarmed area, but if you are not it just wastes your batttery looking for it.
4. Go to Cellular Data Network.
5. Under Cellular Data:
   • Set the APN to epc.t-mobile.com
   • Leave Username and Password blank
6. Under MMS:
   • Set the APN to internet2.voicestream.com
   • Leave Username and Password blank.
   • Set MMSC to http://mms.msg.eng.t-mobile.com/mms/wapenc
   • Leave MMS Proxy and MMS Max Message Size blank.
   • Set MMS US Prof URL to http://www.apple.com/mms/uaprof.rdf

That is what i did but regular messages seems to work fine but sending a picture message seems to show that its sending then pauses then i get an error message. anyone having this problem?