Since the majority of paintings are not in what could be classified as "Pop Art" paintings and their fans do not have to deal with many of the same issues as the worlds of music or video. Those interested in paintings are usually interested in the art not only for its entertainment value, but also for its expressive qualities. Therefore those interested in paintings tend to want to support the industry and its creators. Thus, there is not the widespread pirating that occurs in say the music world. The pirating that does occur is most often limited to those few stolen images that somebody uses to decorate a webpage for non-commercial use.
Large depositories of high quality images such as CORBIS also aid fans of digitized art. Those interested in digital images of their favorite work can go to sites such as these and download specific works at reasonable prices. Licensing options are also available for those who plan to distribute the work for commercial purposes.
In short, fans of paintings are usually concerned with high quality reproductions and supporting those who are involved in the creation process. Since there are venues that cater to the tastes of these art patrons the painting world is not plagued by the same problems that are common within other art forms.