var Overlayimage = Class.create({
	initialize : function(orig_id, overlay_id) {
		this.orig = $(orig_id).select('img').first();
		overlay = $(overlay_id).select('img').first();
		if(this.orig && overlay)
		{
			this.orig_src = this.orig.src;
			this.overlay_src = overlay.src;
			this.orig.observe('mouseover', this.onMouseOver.bind(this));
			this.orig.observe('mouseout', this.onMouseOut.bind(this));
		}
	},
	onMouseOver : function(e)
	{
		this.orig.src = this.overlay_src;
	},
	onMouseOut : function(e)
	{
		this.orig.src = this.orig_src;
	}
});