Why is my phone saying "unable to share" when I try to change my screensaver?

I have an iPhone 6 with IOS 8.4 and I'm trying to change my screensaver or "wallpaper" to one of my pictures and it's worked before but for some reason now it's saying " Unable to share. There was an error while preparing to share. Please try again later." This happeNed after I was on dubsmash making videos and texting them to my friends. Before I was doing that it seemed to have worked fine. But ever since after I finished making videos on the dubsmash app and texting the videos I made that error has been coming up. I tried deleting the videos (and also some pictures I previously had) I made off my phone, restarting my phone, changing the screensaver to something else and trying to change it to the one I wanted again (which still showed the error), and closing all my apps. If anyone could help me solve this problem that would be really helpful.

Thank you.