Taking a picture from the internet, putting a caption on it and posting it to reddit/tumblr/facebook/twitter/etc. does not make it a meme. Call those pictures what they are; lazy fun…which is fucking fine.
A meme ( /ˈmiːm/) is “an idea, behavior or style that spreads from person to person within a culture.” A meme acts as a unit for carrying cultural ideas, symbols or practices, which can be transmitted from one mind to another through writing, speech, gestures, rituals or other imitable phenomena. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate and respond to selective pressures.
Source: A conversation with my friend Nate. Remember those? Conversations?