use strict;
use warnings;

use LWP::Simple;

my $data_out_file = $ARGV[0] || 'links.txt';

open my $out_handle, '>', $data_out_file
    or die $!;

for my $index ( 0000 .. 1000 ) {
    my $serial = sprintf "%04s", $index;
    my $site = qq(http://somewebsite/65081$serial.jpg);

    sleep 1;

    next unless head( $site );

    my $link =   qq(<img src = ")
               . $site
               . qq(">);
    print $out_handle 
          $link, "\n";
}

close $out_handle or die $!;