From artist:

What I use:

Photoshop + Stable Diffussion

My process/ workflow:
I begin my process by drawing the sketch and coloring it myself. After that, I work on giving it basic shading and lighting, I use AI to refine the image and achieve the desired preference, then, I just fix again some errors and upscale it for a high quality image. ^^

(I always repeat the ai refiniment and drawing it manually for a best result)