In regards to using backgrounds off Pinterest, you shouldn’t since sometimes these people who work hard on backgrounds aren’t given the proper credit they deserve. You may find them pretty and want to use them, but what about the artists who spent their blood and sweat into creating these masterpieces? It isn’t fair to them. Please consider their feelings, and don’t steal their work, thank you : )
P.S Read this thread:
It will inform you very well on background usage ^^
Oh I’d never use if If I wasn’t sure that it was ok. So I’ve actually written a couple of people on pinterest asking to use their backgrounds and how to credit them. But thought that maybe there was some unwritten agreement that when uploaded to Pinterest they are free to use or free to use as long as you credit the artist.