use strict;
    use warnings;

    my %Image = (); keys %Image = 4096 * 128;
    my $rdamt = 4096 * 6;
    my $buffer;
#   my $file = '249465.pprgb-srgb.absv.4000.cs.jpg';     #    Original File downloaded
    my $file = '249465.pprgb-srgb.absv.4000.cs.jpg2';    #    New File multiple copies
    my $compraw = -s $file; my $pixels = int ( $compraw / 6 );
    open ( my $in, "<", "./$file") or die "$!\n";
    while( 1 )
    {
        my $size = sysread( $in, $buffer, $rdamt );    #    No buffering
        if ( $size == 0 ) { last; }
        while( $buffer )
        {    if ( length( $buffer ) < 6 ) { last; }    #    Throw away odd number of pixels
            my $key = substr( $buffer, 0, 6, '' );
            $Image{$key}++;
        }
    }
    close $in;
    my $uniq = keys %Image;
    my $factor = sprintf("%.2f", $uniq / $pixels );

    print "Found $uniq colors in $pixels pixels $factor\%\n";
__END__

##</code><code>##

> time pyrperl uniqcolors.plx
Found 153601 colors in 153606 pixels 1.00% ( File size:  921,638 )
real    0m0.098s
user    0m0.092s
sys     0m0.008s

##</code><code>##

> time pyrperl uniqcolors.plx
Found 460775 colors in 41473710 pixels 0.01% ( File size:  248,842,260 )
real    0m15.015s
user    0m14.937s
sys     0m0.080s