Our sensorium is pretty good at stuff like identifying tigers. There's excellent reasons for this, mainly that being able to distinguish a tiger from a teapot is pretty handy when you're made out of meat. What's surprising and, on the face of it improbable, is that we can identify a photograph or drawing of a tiger. In fact we can identify a pretty poor drawing of a tiger.
I am not a mighty thinker to get this far. Plato was famously interested in it, and built a whole thing around some ideas about it, after all.
Be that as it may, a tiger probably can't identify a photograph of a human as representative of a human. And if it can, well, there's plenty of creatures who can't. There's a whole body of cognitive research classifying which monkeys can and which can't do this sort of task.
A couple of thoughts. Of course we'd develop visual arts that do tickle our sensorium in this way. A method of representing tigers that nobody can identify as such is pretty pointless. What is this welded together pile of melted crayons and paper? A tiger you say? Well, I'm afraid your Rafaelogram isn't very marketable.
Which suggests that there are hypothetical representations of things that make no sense to us, but to someone or something with a differently wired sensorium might well be as clear as a photograph is to us.
I am reminded of a conversation I had some time ago about cognitive development in children. Here is an experiment:
Place some chewing gum in a crayon box, and close it up. Ask a small child what's in the box, and she will say "crayons" most likely. Then show her that it is in fact chewing gum. Now ask her what her friend Tim thinks is in the box. She will, up until an astonishingly late age reply "chewing gum." It turns out that the ability to model the idea that someone else believes something you know to be false is quite a late development.
This sort of thing leads us naturally to a sort of exceptionalism for adults. "Ho, ho, ho" we say, "I'm sure glad I'm not dumb any more" but this is probably untrue. There are probably cognitive tasks we can't handle either. One imagines some hyper-intelligent aliens experimenting on some adult homo sapiens and giggling at the crazy shit this dumbass comes up with.
In the same way, we're probably equally limited in our understanding of representative art. We sort of think we've got it all figured out, but there are surely dimensions to the thing that don't exist to us not because they don't exist, but because we lack the cognitive machinery to imagine them.
So next time you run across some pictures that make no sense to you, keep this in mind. Maybe the artist is just nuts. Maybe it's your own limitations. Maybe both.