4s with Sprint with latest update. When WIFI is turned on, along with MMS and iMessage, I cannot send pictures to other iphone users. I can send pics to my sister who has a blackberry. I can send texts through iMessage to other iphone users, but no pics or videos. When I turned WIFI off, and left iMessage and MMS on, I was able to send pics to iphone users. WTF? Anyone know why this is? The WIFI connection is full signal.