Photography impact in the world of fine art? We can call it the camera obscura ( dark chamber). This device was use long ago before the known camera was created the use of this was to reflect images on a surface to make easy to drawn or paint. This method was use by a lot of known Masters in the Renaissance times. This was the father device, all it was missing was a way to created a surface that would retain the image.
This took a long time but it came to be when Albertus Magnus (1193–1280) discovered silver nitrate, and Georges Fabricius (1516–1571) discovered silver chloride. After this happen was no time till this new discover method would open doors to a new art.
First uses include recording of data on war and family history. Kodak made this affordable and like this a recreational thing. But the artist of the world saw this with big aspirations and use it in everyway possible to created not amazing painting but made it a art own his own. From beautiful landscape photo captures to body figures curves turn into amazing abstract art pieces. No longer needing to have a canvas and bush to be able to created what they saw in their minds but now totally unlimited imagination took over and let them made art of anything they could think of. This also made possible to put a face on the authors of books and stories even criminals.
On this modern world of art and advertisement it gives wings to this art and Photoshop and other computer programs made the unreal real seeing real is a lot more that can be said about photography influencing illustration and graphic design but all this can be answer by opening your eyes. We are totally surrounded by graphic design work and illustration photography give a humanistic feel to this art work. And help transmit the messages. Without photography we could never seeing half of the things we do today and we probably would still be on the cave ages. Maybe not just holding still for days waiting on a painter to get the strokes right.