function newImage(arg) {
    if (document.images) {
        rslt = new Image();
        rslt.src = arg;
        return rslt;
    }
}

function changeImages() {
    if (document.images && (preloadFlag == true)) {
        for (var i=0; i<changeImages.arguments.length; i+=2) {
            document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
        }
    }
}

var preloadFlag = false;

function preloadImages(){
    var currUrl, currImgName, currImgSrc, dot;
    if(document.images){
        for(i=0;i<document.images.length;i++){
            currImgName = document.images[i].name;
            currImgSrc  = document.images[i].src;
            if(currImgName.substr(0,4) == 'roll'){
                dot = currImgSrc.lastIndexOf('.')
                if(dot>0){
                    currUrl = currImgSrc.substr(0,dot-3) + '2_' + currImgSrc.substr(dot-1,1) + '.gif';
                    eval("var roll" + i + " = new Image();");
                    eval("roll" + i + ".src = '" + currUrl + "'");
                }
            }
        }
        preloadFlag = true;
    }
}