Website folder real time unprotect/protect from HTML

I have a website with two areas - free access & members' only access. Member user names and passwords reside in a data directory outside HTTPDOCS. A Perl htaccess file in the page template directory restricts members' access to that template. I want the HTML index file in the template directory to change the permission in the graphics folder each time it opens and closes and to allow access when someone clicks to enlarge the image to full HD size if the person is a registered member and to restrict the permissions to standard definition images if that person is not a member. Any questions please ask. Bids cannot be accepted from the USA or US dependent territories for legal reasons, and from Islamic countries because of the website content.