How to make launchy 2.0+ skins?

Question

How do I make skins? I'd assume its just changing the pictures but there's some css and other stuff there aswell and I'm not sure what to change.

Also, does the size of the skin's image change the size of the skin? For example if the skin is 1920x50 could i make it cover the top section from edge to edge on my 1920x1080p display?

Thanks!