Tim S. Not an expert but all underlying models have general disclaimers that give you the creator commercial rights for use. I have used AI in six books and all I did was include the general note that I actually got from support teams at Flux, OpenAI etc i.e. at model level. But for all models you are the owner. But doesn't mean that someone else may not generate something similar or matching. That is a different domain and I have little guidance on that. BTW...same applies to logo. But I applied for trademark to one of mine. And always take the logo generated but then use some high quality software to sharpen, change the color paletter and add something that differentiates outside of the model. I know it sounds funny but in my case I had a logo of the rising sun. I changed the orange to gold and added two small birds flying in the backdrop. Sorry for the long answer but just wanted to share.