I know this question has been asked before, I've searched through this site but the answers didn't help me so I'm trying again.
I have a site where the background is an image with 100% fill. I want that image to fade into another image as you scroll down the page and read the text.
I'm new to all this, don't assume I know the basics when you answer the question, assume I do not know anything. I'd rather have you explain the obvious than jump over something I don't know yet.