var myimages=new Array()

function preloadimages(){
for (i=0;i<preloadimages.arguments.length;i++){
myimages[i]=new Image()
myimages[i].src=preloadimages.arguments[i]
}
}
preloadimages("images/blank.gif",
    "images/order/back_on.gif",
    "images/order/continue_on.gif"
)

function changepic(img_name, img_src) {
    document[img_name].src = "../images/order/" + img_src;
}