This quote from Ayn Rand is the best definition of art I have ever come across. It covers all art. People know what appeals to them. Art that touches their metaphysical value system will be in harmony with their soul. Every person is an individual, so is each painting, each style.
Every painting ever painted comes from the soul of an artist.
I am not a photo realist. Nor do I try to be. I sometimes use photos as a reference for my work. Sometimes I use life, and sometimes my imagination will suffice. As a Romantic Realist painter, I try to improve on nature.