Impressionism is like reading between the lines and inferring something...
Impressionism, Realism, Cubism and the avant-garde art is not exactly arranged in chronological fashion. Perhaps everything happened at a different time and different space but had one thing in common which is a novelty in the art movement. Avant-garde is a term that derives from the French "vanguard," literally advance guard, and its designation within modern art is very much like its military namesake. Generally speaking, most of the successful and creative modern artists were avant-garde.
Photographic technology rapidly advanced, and within a few decades, a photograph could reproduce any scene with perfect accuracy. As the technology developed, the general public could easily afford to buy the cameras and became increasingly proficient in handling the art of photography. The photograph conceptually posed a serious threat to classical artistic modes of representing a subject, as neither sculpture nor painting could capture the same degree of detail as photography.