var randomTWD = 0;
var DoIt = 0;
images = new Array;
images[1] = new Image();
images[1].src = "images/banner1.jpg";
images[2] = new Image();
images[2].src = "images/banner2.jpg";
images[3] = new Image();
images[3].src = "images/banner3.jpg";
images[4] = new Image();
images[4].src = "images/banner4.jpg";
images[5] = new Image();
images[5].src = "images/banner5.jpg";

function TWDpics() {
var imgnum = images.length - 1;
do {
var randnum = Math.random();
randomTWD = Math.round((imgnum - 1) * randnum) + 1;
} while (randomTWD == DoIt);
DoIt = randomTWD;
document.ImageHolder.src = images[DoIt].src;
}