Can freebox read album art in tags yet? Its been awhile since I have upgraded freebox
It doesn't pull album art from tags i'm afraid although it is probably possible now I am using audio genie it is just something i have not looked at yet. This is mainly due to the fact that most music mangement software will extract the tags for you and if i did add it to freebox it would be done in the config stage anyway so thumbnails could be made.
As well I'm sure most thumbs would be really small since they are generally sized for ipods and other portable players.