var numImages = 4;
var currentImage = parseInt(Math.random() * numImages + 1)
var imagePath = 'Images/';
var images = Array();
for (var i = 1; i <= numImages; i++) {
    var image = new Image();
    image.src = imagePath + "poweredByICE_" + i + ".gif";
    images.push(image);
}

function rotate(item) {
    item.src = imagePath + "poweredByICE_" + currentImage + ".gif";
    currentImage = (currentImage % numImages) + 1;
}