Just what I needed

Great plugin, just what I needed.
I added some code to use the featured image (if there is one) before reverting to the default:
Before this line:
if (!$img && $defimage)
Place the following code:

if(!$img){
  $featured_img = get_post_thumbnail_id($post->ID);
  $imgsrc = wp_get_attachment_image_src($featured_img, 'thumbnail');
  if(!empty($imgsrc[0])) { $img = $imgsrc[0]; }
}

Untick “get first image” and “get first attached image” and the post’s featured image will be used as the thumbnail.