My Music Library Folder Icons

When I rip an album while online Media Player downloads the album cover art
and places it in the album folder. The artist folder displays the album
folder icons on it. this all seems to work fine with a new rip.

I have some album files that do not have icons. I am not sure why. I played
around with a couple of them and finally somehow managed to have the default
icon of the strip of film and a musical note appear. I don't know what I did.

I have 2 questions:
1. How can I have the default icons appear?
2. How can I get Windows Media player to recheck for an album cover and
download it if available.?

--
Mickey