Prepend redirection URL to IMG tags

[bkaul]

I've set up a mirrored image redirection page, like that at http://imgred.com/ and would like it to be automatically prepended to any URL in an [IMG] tag, e.g. http://www.google.com/intl/en_ALL/images/logo.gif would become something like http://imgred.com/http://www.google....mages/logo.gif if wrapped in an [img] tag - I suspect this could be done at bbcode_parse_complete but I don't have the background to actually write the plugin to do it. Currently, we're using a custom BBCode [img2] to do this, but it'd be nice to get this integrated into the default [img] tags for ease of use.

(The purpose of the image redirection site is to automatically locally rehost images rather than leeching bandwidth from the source page)