my $fsize = -s [your file];   ## Find out how big the image is?
my $arrsize = $fsize / 6;     ## Size of the array and hash
my $counter = 0;
my %rgb2c;
keys %rgb2c = $arrsize;       ## Allocate one large memory hash!
my @rgb[$arrsize] = '';       ## Allocate one large memory array!
while ( 1 )
{   $sr_len = sysread(IN, $buf, $bsize);  # SysRead Length    
    last  if $sr_len == 0;      
    while($buf)
    {   $rgb=substr($buf, 0, 6, '');  # Nibble 6 bytes       
        $rgb2c{$rgb}++;
        $rgb[$counter} = $rgb;        # Build array as you go along
        $counter++;
    }
}