handle image attachments recursively

bookwyrm/models/attachment.py

@@ -11,7 +11,8 @@ class Attachment(ActivitypubMixin, BookWyrmModel):
     status = models.ForeignKey(
         'Status',
         on_delete=models.CASCADE,
-        related_name='attachments'
+        related_name='attachments',
+        null=True
     )
     class Meta:
         ''' one day we'll have other types of attachments besides images '''

bookwyrm/models/status.py

@@ -90,7 +90,6 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
         ActivityMapping(
             'attachment', 'attachments',
             lambda x: image_attachments_formatter(x.all()),
-            activitypub.image_attachments_formatter
         )
     ]