use IPC::Run3::Shell { fail_on_stderr=>1 }, qw/convert/;
convert $img, '-auto-orient', '-resize', '300x300', $thumb;

use IPC::Run3::Shell qw/gs/;
gs({fail_on_stderr=>1,show_cmd=>1},
    '-o',$OUTPUT, '-sDEVICE=pdfwrite', ..., '-f',$INPUT);