[crux_]

Instead of mirroring, you could proxy. (Solves "storage"/"mirroring" issue; doesn't solve "nasty stuff served up through your server" issue.)

In general, though, there's no way around it, except of course by restructuring gifexplode as a bookmarklet or convincing image host(s) to partner with you:

They can then include the code on the pages they serve up themselves, allow XHR requests via HTML5 or flash mechanisms, or give you base64 data smuggled into a JSONP.

[user24]

Thanks, yeah I think proxying is the best solution. I'm still not sure if that's a route I want to go down though... The nasty stuff served through my server is what I want to avoid. Gifexplode became quite popular on 4chan you see...