Henri Rousseau – People Strolling in a Park

The figures in this painting look slightly off in both pose and scale, a result of Rousseau never having received formal art training — he never learned perspective or human proportion in any academic setting.

And yet, even while painting people on a tiny scale, he still bothered to render details like the folds of their clothing — a distinctive quality that may only have been possible because he hadn't been trained in the conventional rules. It's quite possibly this very quality that drew people to Rousseau's work in the first place.