$(function() {
  $('.roll img').hover(
    function() {
      var img = $(this).attr('src').replace(/_(on|off)\./, '_on.');
      $(this).attr('src', img);
    },
    function() {
      var img = $(this).attr('src').replace(/_(on|off)\./, '_off.');
      $(this).attr('src', img);
    }
  );

  $('.bright').hover(
    function() {
      $(this).css({'opacity':'0.9','-moz-opacity':'0.9','filter':'alpha(opacity=90)'});
    },
    function() {
      $(this).css({'opacity':'1','-moz-opacity':'1','filter':'alpha(opacity=100)'});
    }
  );
});