var randomImg = new Array()

randomImg[0] = 'images/HOME21.jpg'
randomImg[1] = 'images/HOME10.jpg'
randomImg[2] = 'images/HOME8.jpg'
randomImg[3] = 'images/HOME22.jpg'
randomImg[4] = 'images/HOME7.jpg'
randomImg[5] = 'images/HOME6.jpg'
randomImg[6] = 'images/HOME9.jpg'
randomImg[7] = 'images/HOME3.jpg'
randomImg[8] = 'images/HOME4.jpg'
randomImg[9] = 'images/HOME5.jpg'
randomImg[10] = 'images/home15.jpg'
randomImg[11] = 'images/HOME13.jpg'
randomImg[12] = 'images/HOME45.jpg'

var imglen = randomImg.length;

var preBuffer = new Array()
for (i = 0; i < imglen; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = randomImg[i]
}

var whichImage = Math.round(Math.random()*(imglen-1));
function showImage(){
document.write('<img style="width:951px;max-width:949px;" src="'+randomImg[whichImage]+'">');
}