my $t = time;
$img-> Set( compression => 'Zip' );     # default compression level
printf "Size: %d \t Time: %.2f\n", length $img-> ImageToBlob, time - $t;
$t = time;
$img-> Set( compression => 'Zip', quality => 10 );
printf "Size: %d \t Time: %.2f\n", length $img-> ImageToBlob, time - $t;

__END__

Size: 13868590   Time: 11.41
Size: 15694516   Time: 1.92