Depends on what the image is for. If it's a basic image of a character, just to give us a clearer idea of what they look like, I guess it's fine, might help people who struggle with visualizing characters. But if you're using them for scenes or even like a comic or Manga panel... that's a no for me. At that point, it almost feels like you don't believe in your own writing if you feel AI images can better convey a scene than your own words. Covers, whatever, we can't all afford it. But art between chapters being AI is off putting to me. A cover is how you draw people in to read, but the images between chapters don't serve to draw attention to your writing, it just recreates a scene you already described. And while I obviously don't speak for everyone, I have definitely seen some polls on other writing forums that had lots of people who thought the idea of AI art in chapters added nothing to the experience, and depending on where the art was placed, actually just made them drop it altogether. So while I'm not personally a fan, I think you'll be fine as long as you place the images at the end of the chapter, not in the middle.