+ $file =>
+ -delete => '1--1',
+ $aspect ? ('+distort' => SRT => "0,0 1,$aspect 0") : (),
+ -thumbnail => $opt{size} || '40x12',
+ -colorspace => 'gray',
+ '-normalize',
+ -level => '-1%',
+ -channel => 'A', -threshold => '50%',
+ -background => 'black',
+ -layers => 'flatten',