function initRollOverImages() {
    var image_cache = new Object();
    $("img.swap").each(function(i) {
			   var imgsrc = this.src;
			   var dot = this.src.lastIndexOf('.');
			   var imgsrc_on = this.src.substr(0, dot) + '_over' + this.src.substr(dot, 4);
			   image_cache[this.src] = new Image();
			   image_cache[this.src].src = imgsrc_on;
			   $(this).hover(
			       function() { this.src = imgsrc_on; },
			       function() { this.src = imgsrc; });
		       });
}
$(document).ready(initRollOverImages);