<div id=mydiv>

<img src=myimage.jpg />

</div>

<script language=javascript>

var a=document.createElement('a');

a.href='http://mylink.com';

document.getElementById('mydiv').appendChild(a);

</script>

The script doesn't work to create link on image

<div id=mydiv>

    <a href=http://mylink.com><img src=myimage.jpg /></a>

</div>