Selling High-Res Digital Files to Small-Time Artist—Please Help!

MoonMan04

Hello! I've now had a few artists reach out to me asking me to purchase a high-res file. I've never sold a high-res file, although I'm sure these artist that are requesting my files aren't likely trying to take advantage of selling my image in other ways I still want to proceed with caution. Here are a few thoughts:

What would be a fair price to sell a high-res digital file to a small-time artist? For example, the two recent artist I've encountered were wanting to use my prints to do a wrap on some cornhole boards and also to burn my image on ceramic tiling.

What kind of document should I draft up to ensure my work is only being used for what they promise?

Should I ask for royalties instead? but how do I track this on their end?

If anyone has any experience in selling high-res images in general or have any wisdom on the subject, I'm all ears! Thanks for the help folks.