This "borrowing" was a common practice at the time and it didn't seem to hurt his reputation; in fact, the famous painter Henry Raeburn was commissioned to paint him several times.
Da das damals nicht unüblich war, schadete es anscheinend nicht seinem Ruf; tatsächlich wurde der berühmte Maler Henry Raeburn mehrmals beauftragt, ihn zu porträtieren.