Check post-images and post-attachments relations by related name

boards/models/post/__init__.py

@@ -310,12 +310,12 b' class Post(models.Model, Viewable):'
         """
 
         for image in self.images.all():
-            image_refs_count = Post.objects.filter(images__in=[image]).count()
+            image_refs_count = image.post_images.count()
             if image_refs_count == 1:
                 image.delete()
 
         for attachment in self.attachments.all():
-            attachment_refs_count = Post.objects.filter(attachments__in=[attachment]).count()
+            attachment_refs_count = attachment.attachment_posts.count()
             if attachment_refs_count == 1:
                 attachment.delete()