Machines can beat humans at chess, but how is that different from creating a work of art? It may be necessary to first define what a work of art is. Merriam-Webster gives the following definition: Art is the conscious use of skill and creative imagination especially in the production of aesthetic objects.
The key word here is “conscious.” Consciousness is necessary in order to imagine, as well as to judge aesthetic value. An experience is necessary, and machines cannot experience. All they will ever be able to do is process data.
A machine may be able to recognize faces, colors, shapes, sounds, perhaps even tastes, but no matter what comes in, it will be data, not personal experience. Art making involves experiencing something in your consciousness, and then translating that experience into colors and forms, sounds, or words, so that others can have a glimpse of that same experience.
A painting is not a photograph. A photograph captures the physicality of the object, but a well painted portrait will capture something beyond that. The person in love sees his or her beloved differently than the rest of the world does. This is the foundation of art. And a machine will never see anything differently than it objectively is.
Even if a machine could take in signals and recognize sights, sounds, tastes, smells, etc, it would not be able to translate that experience into a work of art, or into a well-written piece of prose. The only way a machine could ever know whether something is beautiful or desirable is by studying consensus. If many people have clicked “Like” on a photo on Facebook, a machine may conclude that it is a good photo, or that the person in the photo is attractive. But making art that’s worth looking at implies novelty. It means creating something that didn’t exist before, something that doesn’t copy anything else. A data processing machine cannot deal with novelty, with anything new, because there is no data pertaining to it. A machine may be able to create by trial and error, trying out combinations of colors and forms (in art) or notes (in music) but without a consciousness to experience the impact of that creation (how do you judge impact in purely materialistic/physicalist terms?), and to further refine, and refine, and refine it (an integral part of all art), all machine-made art will remain very badly made at best.
In closing, when looking at a piece of art, consider whether a machine could do it. If the answer is yes, perhaps what you are seeing is not real art.