I don’t think you understand what the concept of mutation/remix is then. “A horrified Luke sees his family killed” and then writing over it something cheeky about newfound freedom vastly alters (mutates) how the image is interpreted. “Selectice Pressures” could be something like a topical joke based on current events, in this case it’s the fact that he was signing cards at a convention, so the fan boy joke was informed by that situation.

A meme doesn’t need a multitude of variations to be considered a meme, that’s just going viral. It also doesn’t need to be a photoshopped image, changing the text is creation of a new meme, think advice animals. Simply changing how the image is received by a viewer is enough to be a meme, it’s nothing more complicated than that.