I'd hope you'd look to your httpd first to handle this sort of access control. Apache's .htaccess files my fav way to keep people where they should be. 
AuthType Basic
AuthName "Squid User Access Reports"
AuthUserFile /usr/local/apache/conf/passwords
<Limit GET POST>
order deny,allow
deny from none
allow from all
require valid-user 
</Limit>

[download]
Which is sloppy in some ways , this could certainly be more secure, giving your cgi carte-blanche to send users hither and thither IMHO is pleading for trouble. Doing this kind of ACL on an image by image basis ... would be pretty tricky though. Other things I've seen done , serialize your imagenames to death when they're created - so folks aren't able to guess them. Getting off topic now. bad karma. --shout down now!

In reply to Re: Re: restricting public access to images by submersible_toaster
in thread restricting public access to images by uzzikie

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.