I've been using Roxio Disc Copier to convert some Divx music videos to ipod format. When I add the converted files to iTunes, the thumbnail usually just shows as completely white. I've tried using the 'Set movie thumbnail' option, and sometimes it works, but more often than not it doesn't. The strange thing is sometimes I'll convert a file and the thumbnail shows as white, but then I'll try converting it again, and it might show ok. Anyone have any ideas?