Join (free) BerninaV6Software group on Yahoo groups. Go to groups.yahoo.com
Once you have access, use the search for Portfolio Icons. There has been extensive discussion. "This is not a v6 issue, but an issue with Windows."
I bought a very easy to use $25 program called Sew Iconz from
http://www.sandscomputing.com and now see all my thumbnails.
hth
Susan