Emil Flohri deserves a place here. He is a well-known political cartoonist. But that aside, he painted many silent-screens portraits. He worked at Disney studios too.
As much as I love Henry Clive it is Flohri's Valentino portrait which I think sets him apart.
Motion Picture Magazine (1922) 
Motion Picture Magazine (1927)
Belgian for Son of the Sheik
The artist with his assistant
