#!/usr/bin/perl -w
use CGI;

# Where the image files are.

my $imagedir="images";

# You shouldn't need to change this.

my @file_types=qw/ jpeg jpg jp2 jfif jng png mng gif bmp /;

# ==
# Nothing changes below here.

my %file_types_h;
@file_types_h{@file_types}=@file_types;
my $cgi=new CGI;

sub cdie {
  print $cgi->header("text/plain");
  print "ERROR: ";
  print @_;
  exit;
}

opendir(IDIR, $imagedir) or cdie("Data directory not readable");
my @items=map {"$imagedir/$_"}
 grep {m/\.(\w+)$/ and $file_types_h{$1} and -r "$imagedir/$_"} 
  readdir IDIR;
closedir IDIR;
cdie("No images to choose from!") unless @items;

print $cgi->redirect($items[rand @items]);