Hi edfx. My name is Straight Talk Charisse. Please create a new APN (Access Point Name). Enter only the settings listed below:
Name: straight talk
Proxy: leave blank
MMS Proxy: leave blank
MMS Port: leave blank
Select the APN you just created and delete the old APN from your phone if possible. Afterwards, try sending a picture message and access your web browser. Let me know if that works. Thanks.