Look at his grip on the club. It’s a right-hander’s grip.
His grip is the correct one for a left-hander. His right hand is at the butt end of the club grip with his left hand at the top of the grip towards the club head. He is posed as if he just took a practice swing and is holding the follow-through. The only thing incorrect about the follow-through position is that instead of looking down the fairway in the direction his hands are pointing, he is looking straight across the ball like he's posing for a camera shot. Being a narcissist, that would seem appropriate.
But right-handed golfers grip the butt end with their left hand, not their right like in the painting.