jQuery.preloadImages = function()
{
  for(var i = 0; i<arguments.length; i++)
  {
    jQuery("<img>").attr("src", arguments[i]);
  }
}

$.preloadImages("/img/bg_header_builders1.jpg", "/img/bg_header_builders2.jpg", "/img/bg_header_builders3.jpg", "/img/bg_header_builders4.jpg");