// Requires mootools
// adds onmouseover to all images with
// class .roll
window.addEvent('domready',function(){
  $$('img.roll').each(function(img) {
    var src = img.getProperty('src');
    var extension = src.substring(src.lastIndexOf('.'),src.length)
    img.addEvent('mouseenter', function() { img.setProperty('src',src.replace(extension,'.hover' + extension)); });
    img.addEvent('mouseleave', function() { img.setProperty('src',src); });
  });
});