Access control for hi-res images?

[ragweed]

I was wondering if there was any way to allow access to all the images with the exception of the high-resolution versions? I have a user that would like visitors to be able to view any of the images in their galleries, but not the high-resolution originals. They would like to limit access to the hi-res images to a specific "higher-privilege" group. Is this possible with CPG?

<for the geeks>
I've considered using mod_auth_mysql and <FilesMatch>require valid-user</FilesMatch> to limit access to the high-res images, but it seems like this level of hackery is a bit extreme..  :-\
</for the geeks>