It's a "easter egg" supposedly that's a game dev. It's because your short cuts are set to something like 48x48 instead of 32x32

It's Tim Cain.

In 1997, because standard resolutions were much lower, very few people used large icons. So Tim Cain's cheery face was used as that icon as an Easter egg. Now, because people use higher desktop resolutions, more people use large icons, and so Tim Cain gets to freak people out more often.