Well i have a method i use its kind of monotnous but it works. Set up a contact in your phone
XXX-XXX-XXXX@pm.sprint.com. Then you send the photo to yourself. You will recvieve the picture in a text message, and when you recieve it you will have the option to forward the picture and you can send it to any number without having to remember all these silly addresses. yes it takes a few extra steps but i've had a 100% success rate! Good luck and i hope this helps!!!