A painting, unlike other forms of art, is unique in the way it brings the viewer into an enhanced vision of reality. It does this in a way that a photograph is able to imitate to a certain extent. I'll explain why.
Have you ever wondered how a lovely scenery may remind you of a painting that you admire? Actually the converse is equally true; the lovely painting is what helps you to appreciate the scenery. The human mind does not process 100% of what the eye takes in. It subconsciously plays down unnecessary details and focuses on what it likes or chooses to see. The artist puts into his painting what the mind "sees". He leaves out a great deal of extraneous details and concentrates on the vital elements that make a great picture. He uses textures in his strokes to further achieve the desired effect. He uses colour in a way that non-artist have not been trained to do. For example, many people see the cloud as white in colour, but the painter would add a tinge of other colours to enhance the effect. Pure white alone does not replicate the real cloud, if you are observant enough.
A photographer is like a painter. The camera was invented to capture an image as realistically as possible, yet an exact copy of the real world is not what makes a great picture. It is the enhanced reality created by a seasoned photographer that makes an image appealing. In the enhanced reality, the photographer uses selective focusing and creative lighting (to put it simply) to help the viewer enjoy beauty, more or less imitating the way the mind works. Image editing techniques provide the photographer additional means to enhance the image after the image has been captured.
To this end, one may start to wonder whether photography is really art. I'll leave it to you to ponder and comment.