There are two things you should know about that painting: 1) It's not actually a painting; it's a photo made to look like one, and 2) this movie's casting people did their job a little too well, because the guy in that photo was even scarier than his character.
German actor Wilhelm von Homburg (born under the slightly less intimidating name of Norbert Grupe) first became famous as a sports figure in the '60s, when he was known as "The Beatle Boxer" due to his boyish good looks and scandalously long hair. Even back then, he was creepy as hell. In a 1969 interview, Homburg stopped answering the journalist's questions and just stared at him for minutes, with a faint smile that said "I am strangling you with your own intestines in my mind right now."
Homburg was also part of a wrestling tag team with his former-Nazi-soldier father ... which is kinda shocking, because this was after, according to his father, Homburg raped his stepmother. He was never arrested for that, but he did do five years in prison on charges related to drug dealing and prostitution. Hollywood is the land of opportunity, though, and Homburg's career was resuscitated in the '80s when he was cast as "German terrorist blown up by John McClane" in the first Die Hard. This led to parts in other movies, like Ghostbusters II, where Homburg's rough German accent was replaced with Max von Sydow's comparatively suave voice. They wanted to creep out the audience, not traumatize them.