$(document).ready(function(){
$(".thumb_img").fadeTo("fast", 0.50); // This sets the opacity of the thumbs to fade down to 30% when the page loads
$(".thumb_img").hover(function(){ 
$(this).fadeTo("fast", 1.0); // This should set the opacity to 100% on hover
},function(){
$(this).fadeTo("fast", 0.50); // This should set the opacity back to 30% on mouseout
});
});