I know this was a much debated item a while back and I did found some info on it in the sketchbook sticky section.
But.. ever since they updated the attachment manager wich now enables you to put text between your images, the help given there doesn't apply anymore.
Or maybe it's just me, but I can't change my sketchbook thumbnail , even if I put a new image as the first one in my first post.
attached images also now just show up as regular uloaded pictures and not with the box arround it stating it's attached anymore.
does anybody know?