Simpler to use a split; "\?"
Code:
#!/usr/bin/perl
use strict;
use warnings;
my $URLstring = "http://gallys.40somethingmag.com/images/BettyBlaze_28866/?nats=XXXXXXXXXXXXX";
our @url = split /\?/, $URLstring;
print $url[0] ."\n";
exit;
#output
#12:24 AM barry@server:~/Desktop$ ./split.cgi
#http://gallys.40somethingmag.com/images/BettyBlaze_28866/
or regex then just substr 0, -1 ( in perl chop $url[0];)