var theQuotes = new Array()

theQuotes[0] = './img/quote01.gif'
theQuotes[1] = './img/quote02.gif'
theQuotes[2] = './img/quote03.gif'
theQuotes[3] = './img/quote04.gif'

var j = 0
var p = theQuotes.length;

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

var whichImage = Math.round(Math.random()*(p-1));
function showQuote(){
document.write('<img src="'+theQuotes[whichImage]+'">');
}