function ImageRoll()
{
	this.register = function(id, dest, extra)
	{
		var img = document.getElementById(id);
		if (!img) return;
		
		var src = img.src;
		var dest = this.getDestSrc(src, dest);
		
		img.onmouseover = function() { this.src = dest; }
		img.onmouseout = function() { this.src = src; }
		
		if (extra)
		{
			var el = document.getElementById(extra);
			el.onmouseover = function() { img.src = dest; }
			el.onmouseout = function() { img.src = src; }
		}
		
		this.preload(dest);
	}
	
	this.getDestSrc = function(src, dest)
	{
		return (dest.indexOf("/") == -1) ? (src.substr(0, src.lastIndexOf("/") + 1) + dest) : dest;
	}
	
	this.preload = function(src)
	{
		var i = new Image();
			i.src = src;
	}
}