foreach $file (@ARGV)
{
    $f = $file;
    $f =~ s/\.\w+$//;
    
    &cmd("djpeg $file | pnmscale -pixels 25000 | cjpeg -quality 85 > $f.tn.jpg");
}

sub cmd 
{
    local ($cmd) = @_;
    print "cmd: $cmd\n";
    system ($cmd);
}