How about this?
Code:
mkdir /mnt/us/screensaver
test -d /opt/amazon/screen_saver/600x800_ || mv /opt/amazon/screen_saver/600x800 /opt/amazon/screen_saver/600x800_
ln -sf /mnt/us/screensaver /opt/amazon/screen_saver/600x800
This way, you can even run it again without fear of losing the original screensavers or screwing up the fs hierarchy