In my theme, thumbnails are working just fine for the most part. But when I preview a post by clicking the "Preview changes" button, about 3/4th of the thumbnails on the page are broken. When I test with has_post_thumbnail() or get_post_thumbnail_id(), nothing is returned indicating that no thumbnails are associated with the posts.
Again, the odd thing is everything works just fine on published posts. Any idea the cause?
