They are from an illustration of how big wikipedia would be if it were printed in books like volumes of a typical encyclopedia. Unfortunately, it is misrepresented here, because they only show the equivalent of 4 bookshelves in this meme, when the original illustration was 17 shelves (about 4x what is pictured here). So basically, wikipedia would comfortably line the walls of an average-sized study. Source: WIKIPEDIA - Size in Volumes

Interestingly, the link I just shared would fall under the category “Lording it over Britannica” in OP’s meme.