People say things like "art is communication" or "art is primarily about communication". People like me say things like that. I'm pretty sure it's a point of view I have expounded. It's also not quite right.
Communication involves one party putting information into a medium, and another party taking the same information out. I make noises with my mouth, they travel through air to your ear, where you hear them and understand my words. I encode 1s and 0s as pulses of light onto a fiber optic cable, a device at the other end decodes those pulses into the same sequence of 1s and 0s. I take a picture of a rose, trying to capture the sublime in the rose; you, looking at my picture, feel the sublime in the rose.
While this is how it works in some idealized sense, in reality it often does not. More importantly, there's no particular reason it must. A good piece allows the viewer to take something out, to be sure. A good piece makes you feel something, and the sublime in the rose is a perfectly good thing for a piece to make you feel. The part where the artist puts that in, though, that's not necessary. The picture could be an accident, or the intentions of the artist could be something else entirely. In general, the very best an artist can hope for is that the viewers receive something that is loosely related to what the artist had in mind. At worst, of course, nothing whatever is received.
An artist can even have a coherent idea about what should be received, without knowing what should be received. An artist might intend that the viewer see themselves more clearly, or that the viewer be confronted with their own idea of "this mountain." As artist might simply intend the work as a mirror or a window, either literally or figuratively, to something else that the artist cannot or does not want to predict.
The point of art is that the viewer receives something. It's not that the artist sent anything, or that if so the viewer received what was sent. It's just about receiving, and that's not communication.