$(function() {
	rollovers(); 
}); 

function rollovers() {
	$('.rollover').mouseover(
		function() {
			var source = this.src;
			var source_trunc = source.substring(0, source.length - 4); 
			this.src = source_trunc + '_mo.png'; 
		}
	).mouseout(
		function() {
			var source = this.src;
			var source_trunc = source.substring(0, source.length - 7); 
			this.src = source_trunc + '.png'; 
		}
	); 
}