Both photography and image generation by computers are techniques that you can use in the ancient discipline of painting, aka "putting colors on a surface to produce a visual effect". Since its invention, photography has been a staple tecnhique for many painters. I don't see why "AI" should be any different.

Leonardo used the camera obscura as part of the creation of some of his paintings. Rockwell worked from photographs to produce most of his illustrations. Many serious artists in the future will certainly spend time crafting prompts.