There is not much to worry about it regarding memes. Usually memes already have watermarks and mostly its free to use.
Just check the copyright notice on the websites you get it from.
And fyi, copyright is just a threat of force saying, don't steal my ideas or else.
You mean I didnt have to get all dramatic then?!?!? Bugger . . .
(Btw when i first saw i was tagged on a post called 'Information about penguin' I was like what did lucylin do again, and what secrets has been revealed that I have to be taged on??? Paranoid much? LoL)