Let's add a semi-transparent effect to the thumbnails, and each thumbnail will get back to its full opacity when hovered over.
This can be easily implemented via the two built-in CSS class:
thumb and
thumb-on:
#thumbs .thumb img{ opacity:0.6;filter:alpha(opacity:60); }
#thumbs .thumb-on img{ opacity:1;filter:alpha(opacity:100);}
That's all there is to it.
