I have had an iphone for years and have never experienced this problem. With my iphone 5 (at&t carrier), if I don't have my wifi turned on I won't always received pictures in text messages. I will be on a group text and everyone will be commenting on a picture I can't see! Or family members will send me a picture and when they ask what I thought about the picture, I have no clue what they are talking about. And when I ask someone to resend it, it miracously works if the wifi is on. The thing is, I have great signal when the wifi isn't turned on (LTE is showing).
I went in to the apple store, and of course "they couldn't duplicate the problem", but it keeps happening and it's beyond annoying! I don't want to keep my wifi on because it drains the battery. Anyone else have this problem, or can you suggest something to fix it? And yes, I have already restarted and restored my phone to factory multiple times to try and fix this, and had no luck.