"It is well to remember that a picture- before being a battle horse, a nude woman, or some anecdote- is essentially a plane surface covered with colors assembled in a certain order."
"Definition of Neotraditionalism"
I would attempt to argue that any digitally created art, despite its aesthetics, is subject to classification by its output medium, the ink-jet print.
Lets compare three imaginary works of art: a digital painting, a digital illustration, and a digital photograph. Before any subject matter is apparent, the physical presence is a collection of colored micro-fine dots arranged by the print head as directed by digital data. The output and how it is constructed is identical for each of the apparently different artworks.
The creation of each apparently different artwork is also similar. Digital information such as Ones and Zeros is created and manipulated. If the data is manipulated with a 'brush tool' or a 'levels tool' the fundamental result is the same- data has been changed from one state to another.
To the person who would argue that an ink-jet print which looks like a painting or a photograph should be labeled as such, I would point out the surface is the defining characteristic of the medium. A photographic print contains light sensitive silvers; a painting is covered in pigments deposited by their medium. The process of creation for each work is just as different as its surface.