Art is the ultimate expression of the individual. It's a celebration of the individual. To quote Mises:

"All rational action is in the first place individual action. Only the individual thinks. Only the individual reasons. Only the individual acts."

He is referencing economics but nothing expresses individualism in a more tangible way than art in this regard. You can't be a collectivist and be a true lover of art at the same time since art so clearly illustrates individual action.