18+ Psyche and Cerberus. Wilhelm von Kaulbach. 1830/31. (marked NSFW because Psyche is topless) ( lemmy.sdf.org )

Image Description: A three-headed dog sits on the left of the image. To the right, a woman fleas while holding out a piece of bread or cake to the dog. She is topless and wears a robe. She has a scroll? in one arm. Her hair is long and dark. She is barefoot.
Two of the dog's heads are eagerly reaching up for the bread. The third is licking his back. The pup is a very good boy. The necks are long and flexible. The dog has short hair and spots, and a long tail. It looks maybe like a greyhound.

Found at: https://commons.wikimedia.org/wiki/File:Wilhelm_von_Kaulbach_-_Das_M%C3%A4rchen_von_Amor_und_Psyche,_Psyche_und_Cerberus_-_10438_-_Bavarian_State_Painting_Collections.jpg. In Bavarian State Paintings collection.