Regarding authenticity, the difference between "by" and "after" Gilbert Stuart when considering a purchase of a Stuart portrait

Those of you thinking of investing in a masterpiece by Gilbert Stuart, perhaps by auction, pay close attention to the wording which describes the portrait.  Also the price range is an indication of authenticity.  Authenticity of Stuart portraits is always an issue of importance to consider, as he never signed his portraits.  He considered the entire portrait as his signature.

If the wording includes "after", this indicates that the portrait is a copy of the Stuart style.

Gilbert Stuart was the rage at the time he was engaging in his art, thus his style of portrait painting became popular (unless of course the sitters wished to have a more flattering image!). People also respected the Stuart style because the artist was actually earning money from his artwork...a novelty indeed.

Here is an example of a fine portrait. 

This is James Barton, founder of Milford, PA's Cold Spring Water Company

Starting price at auction for this painting is $2000.00

Although it has many seemingly authentic Stuart touches, do you think it is "by" or "after"?

Naturally the most important aspect to consider when viewing a portrait... when the question of authenticity comes up.  Does the portrait jump off the canvas?  Is it so beautifully realistic that it looks like a photograph? So true-to-life that you feel you could cup his face in your hands, begin to talk to him?

This portrait is "after" Stuart.

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