I understand all of the words other than "クソ" in the phrase "クソコラグランプリ". "コラ" means photomontage, photoshop or the like (from "collage"?). "グランプリ" transliterates as "grand prix", which roughly means competition.
But what about "クソ"? Its literal meaning is faeces, and some people have translated the whole phrase into English as crappy collage grand prix. I'm suspicious that it doesn't have a nuance of inferior quality, which is a common meaning of "crappy" these days. Instead, might it have a nuance of extremely unpleasant, or maybe be used as an intensifier?
Kotaku mentions that the phrase has previously been used in the context of Final Fantasy 15.