[HotHunt]

The painting shows his follow-through swing as correct for a left-hander if he has taken his stance and a practice swing and is going to hit the ball to his right.

But if he plans on hitting the ball to his left down the fairway, he is shown incorrectly as a right-handed swinger.

I think the painter got it correct.

[Ancient Man]

Look at his grip on the club. It’s a right-hander’s grip.