I would like to make my 4images gallery so that users need to become registered members in order to see the full-sized images. This is easy to set up by changing the category properties, but when I do this it takes the links away from the thumbnails. What I'd like to do is make it so that when a non-registered user goes to a category page, it shows the thumbnails and makes them all link to a page that says "you must be a registered user to see the full sized image." I have done some hunting in the code, and it looks like the variable $show_link is responsible for this action (in functions.php). Could someone give me some advice on how to make it so that non-registered users see thumbnails that all link to one place instead of the full-sized images but registered users see thumbnails that link to the full-sized images?
Thanks very much for the help!