@D.C Style The "Edit Thumbnail" button currently appears on forum posts where the add-on doesn't apply. I think it should be hidden to avoid user confusion.
If a user posts a YT video I understand this will work to show the YT frame as the thumbnail, great. But if we feature the thread, will it show as the featured image? That usually grabs the first image of the post but hoping it could use the thumbnail in this case since there would be no other image.