var bufferImage = new Array();

function Buffer(filename) {
    var i = bufferImage.length;
    bufferImage[i] = new Image();
    bufferImage[i].src = filename;
    }

function showImage(filename) {
    document.images[Image_Name].src = filename;
    }

Image_Name = "SHOWPAD";

Buffer("01.jpg");
Buffer("02.jpg");
Buffer("03.jpg");