The role of fine art has been to simultaneously express values of the current culture while also offering criticism, balance, or alternatives to any such values that are proving no longer useful. So as times change, art changes. If changes were abrupt they were deemed revolutions. The best artists have predated society's changes due not to any prescenience, but because sensitive perceptivity is part of their 'talent' of seeing.
Artists have had to 'see' issues clearly in order to satisfy their current clients, yet not offend potential patrons. For example, paintings glorified aristocracy in the early 1600s when leadership was needed to nationalize small political groupings, but later as leadership became oppressive, satirization increased and subjects were less concerned with leaders and more with more common plights of mankind.
Examples of revoutionary art in conjunction with cultural/political movements:
But not all artistic revolutions were political. Revolutions of style have also abruptly changed the art of a culture. For example, when the careful, even tedious, art techniques of French neo-classicism became oppressive to artists living in more exuberant times, a stylistic revolution known as "Impressionism" vitalized brush strokes and color. Edgar Degas, Claude Monet, Pierre-Auguste Renoir burst onto the French culture, effecting a revolution with a style that has become commonplace today.
An artistic revolution can be begun by a single artist, but unless that artist gains some understanding, he becomes an iconoclast. The first Abstract Expressionists were considered madmen to give up their brushes and rely on the sheer force of energy to leave an image, but then the import of atomic bombs, all atomic energy, became realized, and art found no better way of expressing its power. Jackson Pollock is the artist best known for starting that revolution.