ED:  The joke's on Mr. Mighty ... that's not even a Rembrandt, it's Vermeer's "Girl With Painfully Heavy Earring".  And true webcomics fans may recognize the Don Quixote in panel 3 (behind the curator's head) as being from Randall Munroe's xkcd (not for the faint of brain).

ERIK: You can't really see it but the painting in the back in the first panel was an intentionally sloppy remake of the same painting that Mr. Bean ruined in Bean: The Ultimate Disaster Movie.  Ah, nostalgia.