$(function(){

	$("img.rollover").mouseover(function(){

		$(this).attr("src",$(this).attr("src").replace(/^(.+)(\.[a-z]+)$/, "$1_on$2"))

	}).mouseout(function(){

		$(this).attr("src",$(this).attr("src").replace(/^(.+)_on(\.[a-z]+)$/, "$1$2"));

	}).each(function(){

		$("<img>").attr("src",$(this).attr("src").replace(/^(.+)(\.[a-z]+)$/, "$1_on$2"))

	})

})