Not much is known about the artist of the original painting,
François Gérard. He was one of the
major students of Jacques-Louis David and a key voice of
early 19th-century art in Paris.
The person, who has been working on Gérard's catalogue raisonné for the last 30 years, is a corrupt dealer. Therefore, any conclusions that he has drawn are suspicious.
(The pictures and information were kindly provided by Ralph Rosen, a professor of classical studies at University of Pennsylvania, and Jon Seydl at the Getty respectively)