Movies make heavy use of computer-generated graphics; they are called computer-generated imagery (CGI) in the film industry. In the 1990s, and early 2000s CGI advanced enough so that for the first time it was possible to create realistic 3D computer animation. The film The Phantom Menace was widely noted for its heavy use of computer graphics.
More affordable computers and software provide several advantages for thrifty artists. Compared to the price of oils, an easel and canvases, a PC and the occasional trip to the copy shop can be an attractive alternative.
There are two main paradigms in computer generated imagery. The simplest is 2D computer graphics which reflect how you might draw using a pencil and a piece of paper. In this case, however, the image is on the computer screen and the instrument you draw with might be a tablet stylus or a mouse. What is generated on your screen will appear to be drawn with a pencil, pen or paintbrush.
The second kind is 3D computer graphics, where the screen becomes a window into a virtual environment, where you arrange objects to be "photographed" by the computer. Of course the image generated is 2D, so you can always take it into your paint program for additions, in the same way Weekly World Inquirer Magazine inserted the space aliens in the coffee bar. Typically, 2D computer graphics use raster graphics as their primary means of source data respresentations, whereas 3D computer graphics use vector graphics.
A possible third paradigm is to generate art in 2D or 3D entirely through the execution of algorithms coded into computer programs. This may be called Proceduralism and could be considered the native art form of the computer. That is, it cannot be produced without the computer. Fractal art is an example.