(I wish that Google Image search had a "Find the copy with the earliest timestamp" option. I originally bumped into this via a share on FB, and used their image lookup search to try and find the original, and it was absolutely no use. I am clearly very tired, because the source is right there, in the bottom-right corner of the image - and now the image link will take you there. But still, how hard would it be for Google to have worked that out for me...)
Original post on Dreamwidth - there are comments there.