var myimages=new Array()
    function preloadimages(){
    for (i=0;i<preloadimages.arguments.length;i++){
    myimages[i]=new Image()
    myimages[i].src=preloadimages.arguments[i]
    }
    }
    //Enter path of images to be preloaded inside parenthesis. Extend list as desired.
    preloadimages("<?=$img_dir?>/header-1.jpg","<?=$img_dir?>/header-2.jpg","<?=$img_dir?>/header-2.jpg","<?=$img_dir?>/header-3.jpg","<?=$img_dir?>/header-4.jpg","<?=$img_dir?>/header-5.jpg","<?=$img_dir?>/header-6.jpg")