'Wish You Were Here' by Canaletto
Son of a celebrity Italian surgeon, the artist Canaletto was named after the alimentary canal, a passage in the body that connects the mouth with the anus.
So it is somewhat ironic that Canaletto devoted his prodigious career to painting vistas of canals of the watery kind rather than studies of human anatomy for the medical profession. I guess he was lucky his father didn't name him Digestive-Tractatto.
Today, Canaletto is considered the father of the modern postcard (similar to those available in the museum shop). Rich patrons commissioned Canaletto to paint picturesque Venetian scenes, add a brief message of the back of the frame, and then send the canvasses to their friends in other parts of the world.
The example above, Wish You Were Here, a view of the Rialto bridge across the Grand Canal, has this message inscribed on its reverse in florid, scarlet ink: "Having a great time with all the ladies. Wish you were here. Love Casanova."