Related to my previous question. The first iteration of my novel had chapters start with quotes from songs and the lyricist's name attributed the next line down. What are the mechanics of that? Do I seek permission from the source or is an attribution enough? I removed them until I found out the legality of it.

I found a painting perfect for my first book cover. It's currently is in a gallery in the midwest but many images exist online. How would I approach them to ask to use it and would it require payment?