diff --git a/keyserver/src/updaters/account-updaters.js b/keyserver/src/updaters/account-updaters.js
--- a/keyserver/src/updaters/account-updaters.js
+++ b/keyserver/src/updaters/account-updaters.js
@@ -116,6 +116,11 @@
     throw new ServerError('not_logged_in');
   }
 
+  // keyserver shouldn't support thick-thread-specific requests
+  if (request.type === 'non_keyserver_image') {
+    throw new ServerError('invalid_parameters');
+  }
+
   const newAvatarValue =
     request.type === 'remove' ? null : JSON.stringify(request);
 
diff --git a/lib/types/avatar-types.js b/lib/types/avatar-types.js
--- a/lib/types/avatar-types.js
+++ b/lib/types/avatar-types.js
@@ -43,8 +43,16 @@
 
 export type UpdateUserAvatarRemoveRequest = { +type: 'remove' };
 
+export type NonKeyserverImageAvatarContent = {
+  +type: 'non_keyserver_image',
+  +blobURI: string,
+  +encryptionKey: string,
+  +thumbHash: ?string,
+};
+
 export type UpdateUserAvatarRequest =
   | AvatarDBContent
+  | NonKeyserverImageAvatarContent
   | UpdateUserAvatarRemoveRequest;
 
 export type ClientEmojiAvatar = EmojiAvatarDBContent;
diff --git a/native/account/registration/avatar-selection.react.js b/native/account/registration/avatar-selection.react.js
--- a/native/account/registration/avatar-selection.react.js
+++ b/native/account/registration/avatar-selection.react.js
@@ -95,7 +95,8 @@
         const clientRequest = selection.updateUserAvatarRequest;
         invariant(
           clientRequest.type !== 'image' &&
-            clientRequest.type !== 'encrypted_image',
+            clientRequest.type !== 'encrypted_image' &&
+            clientRequest.type !== 'non_keyserver_image',
           'image avatars need to be uploaded',
         );
         const newAvatarData = {