diff --git a/bookwyrm/activitypub/person.py b/bookwyrm/activitypub/person.py
index dee6c1f1..118774a2 100644
--- a/bookwyrm/activitypub/person.py
+++ b/bookwyrm/activitypub/person.py
@@ -16,7 +16,7 @@ class Person(ActivityObject):
     publicKey: PublicKey
     endpoints: Dict
     icon: Image = field(default=lambda: {})
-    bookwyrmUser: str = False
+    bookwyrmUser: bool = False
     manuallyApprovesFollowers: str = False
     discoverable: str = True
     type: str = 'Person'
diff --git a/bookwyrm/models/user.py b/bookwyrm/models/user.py
index d1e1f69e..38442ed7 100644
--- a/bookwyrm/models/user.py
+++ b/bookwyrm/models/user.py
@@ -82,12 +82,9 @@ class User(OrderedCollectionPageMixin, AbstractUser):
         ''' send default icon if one isn't set '''
         if self.avatar:
             url = self.avatar.url
-            # TODO not the right way to get the media type
-            media_type = 'image/%s' % url.split('.')[-1]
         else:
             url = 'https://%s/static/images/default_avi.jpg' % DOMAIN
-            media_type = 'image/jpeg'
-        return activitypub.Image(media_type, url, 'Image')
+        return activitypub.Image(url=url)
 
     @property
     def ap_public_key(self):
@@ -106,6 +103,7 @@ class User(OrderedCollectionPageMixin, AbstractUser):
             activity_formatter=lambda x: x.split('@')[0]
         ),
         ActivityMapping('name', 'name'),
+        ActivityMapping('bookwyrmUser', 'bookwyrm_user'),
         ActivityMapping('inbox', 'inbox'),
         ActivityMapping('outbox', 'outbox'),
         ActivityMapping('followers', 'ap_followers'),