Random Image using SSI

I'm trying to write an SSI script that displays a random image. If I have to I'm content with making the page with an .shtml ext, but I've seen pages with an .html extension using the image tag
<BLOCKQUOTE><font size="1" face="Verdana,Arial,Helvetica">code:</font><HR><pre><img src="cgi-bin/script.cgi?blah">[/code]
If possible I'd like to know howto do it that way.

or alternatively you could try it like this...
<script language='javascript'>
var IE4=(document.all) ? 1 : 0;
var NN4=(document.layers) ? 1 : 0;
if (IE4) {
var theSource='<iframe id="Floating" src="whatever.com/cgi-bin/script" width=468 height=61 FRAMEBORDER=0 MARGINWIDTH=0 MARGINHEIGHT=0 SCROLLING=no></iframe>'
document.write(theSource)
} else if (NN4) {
var theSource='<layer id=Floating src="whatever.com/cgi-bin/script" width=468 height=61 style="position:absolute; top:94; left:174;"></layer>'
document.write(theSource)
} else {
var theSource='<img src="static.gif">'
document.write(theSource)
}
</script>
<noscript><img src="static.gif"></noscript>

somebody else suggested this in this forum and it work fine for me (I needed to create a dynamically created html banner depending on the user details to go across mulitple sites). the only thing I added was in case there was neither of the two browsers or no javascript.
tried it in ie, netscape, opera and lynx and it worked fine..


hth


------------------
cheers

Thanks, however I already found out howto do it via CGI/PERL instead of JavaScript. However now that I have the script working, I want to make sure people cannot steal my bandwidth. I was told to use HTTP_REFERER, but I can't seem to find anything about it anywhere.