А если такой:
<script language="JavaScript" class="S">
<!--
var howMany = 4
var quote = new Array(howMany+1);
quote[0]="images/works/1.jpg";
quote[1]="images/works/2.jpg";
quote[2]="images/works/3.jpg";
quote[3]="images/works/4.jpg";
quote[4]="images/works/5.jpg";
quote[5]="images/works/6.jpg";
quote[6]="images/works/7.jpg";
quote[7]="images/works/8.jpg";
quote[8]="images/works/9.jpg";
quote[9]="images/works/10.jpg";
function rndnumber(){
var randscript = -1
while (randscript < 0 || randscript > howMany || isNaN(randscript)){
randscript = parseInt(Math.random()*(howMany+1))
}
return randscript
}
quo = rndnumber();
quox = quote[quo];
document.write('<img src='+quox+'>');
// End -->>
</script>