Gray triangle with upside-down exclamation point when viewing mms pictures HTC ONE M7

[CherrelleLM]

I have a gray triangle that comes up when i try to click pictures sent to me by mms. When I receive the picture I can see it until I try to enlarge it. I tried to do a reboot but I did not root my phone because I heard this was a way to fix my horrible battery life. When I attempted the reboot i initially got a red triangle on my screen, I had to turn it off. Ever since my phone came back on, everything works the same except the problem I have been having with my mms picture messages. Does anyone have any Idea of how I can view my pictures normally again?

Thank you for your responses,

Cherrelle