Perform sever-side caching of 3rd party images
<p>I just added some functionality to <a href="http://www.libcompass.com/" rel="nofollow">my site</a> which, when a user hovers their mouse over a link (to a 3rd party page), a preview of the link is created from the meta tags on the target page and displayed.  I'm worried about the implications of hot-linking in my current implementation.</p>

<p>I'm now thinking of implementing some kind of server-side caching such that the first request for the preview fetches the info and image from the target page, but each subsequent request (up to some age limit) is served from a cache on my host.  I'm relatively confident that I could implement something of my own, but is there an off-the-shelf solution for something like this?  I'm self-taught so I'm guessing that my DIY solution would be less than optimal.  Thanks.</p>

<p><strong>Edit</strong> I implemented a DIY solution (see below) but I'm still open to suggestions as to how this could be accomplished efficiently.</p>