photography opened new doors to those who wanted to capture a moment then paint from a picture. personally i would say that some Photography is fine Art. therefore there is a new media for artists created.
as for Graphic Design, photography radically changed the types of things that can be done with the 2-d image. this is also at a time when print media was the media of Information. photography allowed for a consistent visual likeness that was accessible to the public. i'm sure that many illustrators lost jobs if they didn't change their approach a little. this forced change in approach undoubtedly led to illustrative talent going to all sorts of places.