Right now, for Superman #52, the final new52 Superman book before Rebirth, scheduled for May 25, Comixology is showing just the word Superman written out in the stylized logo on a red background. Previously, it was showing just the Kal-El family crest (aka the big "S" on the Superman uniform). That looks like a placeholder to me, because they don't want to reveal the cover, which may contain a spoiler for upcoming Superman titles.
What do you think the real cover is? Superman dead in SuperDad's arms? Clark Kent's grave? What are some other possibilities?
Oh, also, if you happen to actually know that the cover I am seeing right now is *not* a placeholder, feel free to let me know that, too. Same goes for if you have a link to a website showing the actual cover, and Comixology just doesn't have it yet.