$(function(){
	imageOver();
})

function imageOver()
{
	$("img.on").each(function(){
		var image = this.src;
		var extension = image.substr(image.lastIndexOf("."), image.length-1);
		var image_over = image.replace(extension, "_on"+extension);
		new Image().src = image_over;
		$(this).hover(
			function()
			{
				$(this).css("cursor","pointer");
				this.src = image_over
			},
			function(){this.src = image}
		);
	});
}