function imgRollovers() {
	if (!document.getElementById) return
	
	var preloads = [];
	var images = document.getElementsByTagName('img');
	
	for (var i = 0; i < images.length; i++) {		
		var src = images[i].getAttribute('src');
		
		if (images[i].src.lastIndexOf('nav_') >= 0 || images[i].src.lastIndexOf('_btn') >= 0 || images[i].src.lastIndexOf('_n_') >= 0 || images[i].src.lastIndexOf('_n.') >= 0) {

			images[i].setAttribute('n', src);
			
			if(images[i].src.lastIndexOf('nav_') >= 0){
				var r = src.replace('nav_', 'nav_o_');
			} else if(images[i].src.lastIndexOf('_btn') >= 0){
				var r = src.replace('_btn', '_btn_o');
			} else {
				var r = src.replace('_n', '_o');
			}
			images[i].setAttribute('r', r);
			
			preloads[i] = new Image();
			preloads[i].src = r;
			
			images[i].onmouseover = function() {
				this.setAttribute('src', this.getAttribute('r'));
			}	
			images[i].onmouseout = function() {
				this.setAttribute('src', this.getAttribute('n'));
			}
		}
	}
}

try { window.addEventListener('load',imgRollovers,false); } catch (e) { window.attachEvent('onload',imgRollovers); }