Some time ago, I attended the memorial service for a skilled painter (not exactly a household name, though), and one of the stories told about him was that he visited the municipal museum, where there was a new exhibit of a newly acquired abstract expressionist painting (I believe by Mark Rothko), which just consisted of painted rectangles.

He studied the painting for some time, and then asked to see the director of the museum, to inform him that the painting was hung upside down! When asked why he would think that, he pointed out that wet paint does not flow upward…

So it is indeed possible for a connaisseur to distinguish interesting details in a painting like this.