let me make sure im understanding, you have a picture on page 1 with an id of, say, MyID...when someone clicks on the picture you want to add MyID to the url that is somewhere on page2?

Well lets say the code for the picture in page one is

<a href="page2.cgi?id=MyID"><img src="image.jpg"></a>
[download]

all you'd have to do is get the query string, store it in a scallar(optional) and you could do anything you want with it

#!/usr/bin/perl -w
use CGI qw/:standard/;
use strict;

print "Content-type:text/html\n\n";

my $picid = param('id');
my $url = 'http://www.nextpage.com';

my $newurl = "$url/$picid";
[download]

Using the link i made above this little snip would make a new url http://www.nextpage.com/MyID

hth

Originally posted as a Categorized Answer.