It's spoofing the "facebomb" meme, in which a series of pictures will zoom in on a single individual, and when it pulls back, everyone in the picture has said individual's face. The joke here, of course, is that the Stormtroopers already look identical.
"We can totally test out of summer school physics if we pull this off."
"But we wouldn't be in summer school physics if we could pull this off. I believe my uneasiness is completely understandable since we are the only people in summer school for physics in the history of high school."