I see you solved the problem, but since I already wrote this I'll post it for anyone who can use it. The program traverses the tiff file's image directory chain. Testing on an old 900MHz windoz box, it ripped through 1200 tiff files, over 2 GB, in 23 seconds.

use strict;

my @files = glob "D:/pics/tiff/*.tif";
for (@files){
    my $images = imagecounter($_);
    printf "%40s : %3d \n", $_, $images;
}


sub imagecounter{
    my $tiff = shift;
    my @endian;
    my $offset = 0;
    my $index;
    my $count = 0;

    open (my $fh, "<", $tiff);
    binmode $fh;
    seek ($fh, $offset, 0);
    read ($fh, $endian[0], 2);

    $endian[0] = unpack "a2", $endian[0];
    if ($endian[0] eq 'II'){
        $endian[1] = 'v';
        $endian[2] = 'V';
    }elsif ($endian[0] eq 'MM'){
        $endian[1] = 'n';
        $endian[2] = 'N';
    }else{
        warn "Unknown byte order in $tiff, possible bad file\n";
        return 0;
    }

    seek ($fh, 4, 0);
    read ($fh, $offset, 4);
    $offset = unpack "$endian[2]", $offset;

    while ($offset){
        $count++;
        my $length;
        seek ($fh, $offset, 0);
        read ($fh, $length, 2);
        $length = unpack "$endian[1]", $length;
        $index = ($length * 12);
        seek ($fh, $index, 1);
        read ($fh, $offset, 4);
        $offset = unpack "$endian[2]", $offset;
        if ($count > 100){
            warn "Count too high in $tiff, possible bad file\n";
            return 0;
        } 
    }
    close $fh;
    return $count;
}
[download]