Magick::Image sub_thumb (compact->size().width, compact->size().height, "RGBA", MagickCore::CharPixel, compact->data()[0]);
sub_thumb.magick ("PNG");
sub_thumb.write (tmp_sub_file);
Magick::Image sub_thumb (compact->size().width, compact->size().height, "RGBA", MagickCore::CharPixel, compact->data()[0]);
sub_thumb.magick ("PNG");
sub_thumb.write (tmp_sub_file);