Blank Picture Messages

FIrst, I must say this is the first time I haven't been able to find similar problems with my iPhone in a forum.

I have an iPhone 6 running 8.1.3 although the issue didn't start with any particular update. The issue started, however, on my iPhone 5. I just dealt with it because I thought it would be fixed when I got a new phone. It was not.

The problem is that my picture messages show up blank. Any of the similar issues I've seen just say that they're downloading with the two blue squares. Mine are just blank. An empty blue, green, or gray bubble. When I hit send, the picture slides up like it always has, then vanishes. If the message has text, it only shows the text. You can't even tell there's a picture that goes with it. When somebody sends me a picture, I open Messages, and like when I send a picture, it appears for a split second, then vanishes. All pictures show up in the details screen. None say that they still are downloading.

I've been dealing with this since December. I didn't think it was a big deal, but now it's driving me crazy. Please help.