Proposing this picture for Not Blood Siblings. Tv Tropes seemed to consider this information a spoiler based on spoiler tags, but the picture has been out since February 2013, if not earlier (that is when the first comment is dated too). Unfortunately it's a bit big (the image, the spoiler, I don't think so).
Topic on Forum:Page Images
Get the author's permission if you use this, otherwise, good image, can be resized if need be.
If there is no better alternative I was thinking we could have a caption along the lines of "It's okay because they are not actually related" for the sake of comical redundancy. Perhaps the caption being a pot hole to Department of Redundancy Department.
Don't really have a better suggestion, so go ahead with that.
I just came up with:
having an "image courtesy of…" type of link, have the caption link to the deviant art page and have the picture link to the Friendship Is Witchcraft page (because the image was made for and used in Friendship is Witchcraft).
Or since at least some people at TV Tropes think its a spoiler we could say that "the episode came out in February 23, 2013," and have a link to Late Arrival Spoiler.