#!/usr/bin/perl -w

use strict;
use File::CounterFile;

my $COUNTER       = '/path/to/bg.cnt';
my $DEFAULT_VALUE = 0;

my @BACKGROUND    = qw(
  corner.jpg    anduin.jpg    gandalf.jpg  
  ford.jpg
);

my $c = File::CounterFile->new( $COUNTER, $DEFAULT_VALUE );
   $c->reset if $c->inc > $#BACKGROUND;

print <<EndOfHTML;
Content-type: text/html

<td background="images/$BACKGROUND[$c]">
EndOfHTML