This is probably really easy to guess but very difficult to solve. However I dropped several meta-META hints so even if you guess try to back-solve the meta-nism. And, yes, you'll probably want to google.
There is utterly nothing significant about this image, but in my memory I could have sworn these were Pegasuses (which would make more sense as unicorns aren't part of Greek mythology). That has nothing to do with the puzzle but in an earlier conception I thought I'd have "pegasus" as an entry and I like the Pastoral Symphony. But it has nothing to do with the puzzle.