Many art historians believe this to be the famous painting, Luncheon of the Boating Party (Le déjeuner des canotiers) by the French impressionist Pierre-Auguste Renoir, painted in 1881.
They are right on two counts: it was Renoir, and it was in 1881, but the actual title was The Festival of Slorg, and is much more sinister than art historians have always assumed.
According to Brian A. Oard in his essay on this painting, The Lure of Lotus Eating:
It is a scene of the triumphant bourgeoisie celebrating an appropriately commercialized version of the fête champêtre in a place that was once a playground of the aristocracy. By 1880, nearly a century after the Revolution, the French middle classes were comfortable enough to party like aristocrats, and in Renoir they found their Watteau.
But this is what we see on the surface . . . The horrors of the Slorgfest are too much for me to relate to you here, but I would note that while bottles of wine are in evidence aplenty, you will note that all their plates are empty. And what was on those plates? Well, let’s just say the population of homeless people of Chatou, France is smaller by at least two.
Alltop thinks it shouldn’t be called cannibalism if you only eat one foot. More about this evil painting at Wikipedia.