Topic awaiting preservation: preload image and refresh every 4 hours

Hello,

I am trying to write a script that will allow me to preload and cache an image from a different server. and then display the image on a web page on my site. The image from that server is updated every 4 hours or so. This is basically the preload script I was going to start with:

<script type="text/javascript">
<!--
PreImage1=newImage(88,31);
PreImage1.src="Image1.gif";
// -->
</script>

Can it be done? Any help would be great

Eric

Also:

I wanted to keep the preloaded image in cache only for a few hours before it would be refreshed. That way the image would still be current as it was updated and I wouldnt be constantly taxing their server each time my page was visited.