I used the shadowbox-version 22.214.171.124 and now updated it to the newest version.
Unfortunately it doesn't work anylonger: my pictures were opened not in this cool window, but just in the normal browser-window.
I did't change anything! I even updated to the newest WordPress-version, ...with no result.
So, what is wrong? Also the default-wordpress-theme doesn't show the shadowbox. So it is not up to this "<?php wp_head(); ?>"-thing.
Thanks for replies,