DHTML Image Thumbnail Chooser

<style>
body {
        background-color:#000000;
        color:#E27907;
        font-family:Verdana,Arial;
        font-size:10pt;
        letter-spacing:2;
}
.thumbNormal {
        border:4px solid #000000;
        cursor: pointer;
}
.thumbSelected {
        border:4px solid #ff0000;
}
</style>

<script language="JavaScript" type="text/javascript">
var lastID = 0;
function SelectImg(id) {
        if (lastID > 0)
                document.getElementById(lastID).className = "thumbNormal";
        document.getElementById(id).className = "thumbSelected";
        regex = /_tn/;
        document.getElementById(0).src = document.getElementById(id).src.replace(regex, ");
        lastID = id;
}
function LoadTrigger() {
        SelectImg(1);
}
window.onload = LoadTrigger;
</script>

Click a photo on the left to view full image.
<table border="0">
  <tr>
    <td valign="top"><img id="1" class="thumbNormal" src="/images/family_tn.jpg" width="100" height="50" onclick="SelectImg(1)" /> <br />
      <img id="2" class="thumbNormal" src="/images/ourdog_tn.jpg" width="100" height="50" onclick="SelectImg(2)" /> <br />
      <img id="3" class="thumbNormal" src="/images/fish_tn.jpg" width="100" height="50" onclick="SelectImg(3)" /></td>
    <td width="15"></td>
    <td valign="top"><img id="0" src="" /></td>
  </tr>
</table>