License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Allart van Everdingen. The Ass, Jealous of the Attention the Dog Is Getting From His Master, Looks to Imitate Him by Jumping at the Master's Neck from Hendrick van Alcmar's Renard The Fox, 1650–75. The Metropolitan Museum of Art.