Actually pretty much what you’d expect gif

Misleading Thumbnails - Not always what you think (/r/misleadingthumbnails): This subreddit is a place to share posts (often found elsewhere on reddit), that have the unique quality of generating a Reddit thumbnail that misleads people into seeing something entirely different than what the full-size image ends up being. This almost always occurs in an unexpected fashion, where shrinking down an image to thumbnail-size suddenly creates an illusion one would not have expected. (Only works on Old Reddit or "Classic View")

GIFs (/r/gifs): "GIFs" is officially pronounced with a hard "J"