A "painter" can be an artist who creates with paint and brush, but it can also be a laborer who paints the inside or outside walls of your house. If you say, "My uncle is a painter," without any other context, I would probably assume he paints houses. If you say, "My uncle enjoys painting," I would assume he creates art.
If you said, "My uncle is an artist," I might ask you, "Painter or sculptor?" In this case it would be clearly understood that the "artist" meaning of "painter" is implied.
I hope this is helpful!