$(function() {
   $('#viewNav li').click(function() {
       var clickedClass = this.id;
       clickedClass = "." + clickedClass;
       if($(clickedClass).css('display') == 'none') {
           $('#galleryImages div.image_slide').hide();
           $(clickedClass).fadeIn();
       }
	   $('#viewNav li').removeClass("selected");
	   $(this).addClass("selected");
   });
});