Pictures in text messages not showing

I have had my iPhone for 1.5 years now and never had any issues. All of a sudden, when someone texts me a picture, a flash of the picture will show, then it will disappear and I cannot see it at all. Also, went I try to text someone else a picture, that person will receive the picture just fine; however, I cannot see that I even sent it. I have tried turning off my phone with no help. Please help!!