In the visual medium, what would constitute “high art” versus “low art”—“serious art” versus “bad art”?

What’s the criteria in general? And how should it matter?

Clearly not all efforts at human expression count as “art.”

I guess we can draw comparisons between gallery art VS homemade productions,
works exhibiting great depth/idea and skills VS whimsical doodles,
ballet VS circus,
opera VS Michael Jackson,
avant garde short stories VS paperback fiction,
etc.

In other words, it seems that the work has to take itself seriously?

“Henri Rousseau… was a French Post-Impressionist painter in the Naive or Primitive manner… Ridiculed during his life… he was belittled and even today some art critics regard his art as something nice to look at but not as serious art. Rousseau’s flat, seemingly childish style gave him many critics; people often were shocked by his work or ridiculed it. His ingenuousness was extreme, and he was unaware that establishment artists considered him untutored.” – Wikipedia