Allow images to be sent in Messenger (facebookresearch#1408)

* allow images in messenger

* another check

parlai/messenger/core/agents.py

@@ -93,6 +93,9 @@ def put_data(self, message):
                 'sticker_sender': message.get('sticker_sender', None),
                 'img_attempt': img_attempt,
             }
+            if img_attempt and self.data.get('allow_images', False):
+                action['image_url'] = message['message'].get('image_url')
+                action['attachment_url'] = message['message'].get('attachment_url')
             self.msg_queue.put(action)
 
     def set_stored_data(self):
@@ -137,7 +140,7 @@ def act(self, timeout=None):
         # Get a new message, if it's not None reset the timeout
         msg = self.get_new_act_message()
         if msg is not None:
-            if msg.get('img_attempt'):
+            if msg.get('img_attempt') and not self.data.get('allow_images', False):
                 # Let agent know that they cannot send images if they
                 # attempted to send one
                 msg = None
@@ -146,7 +149,8 @@ def act(self, timeout=None):
                                'Please try with a text-only message.',
                        'episode_done': True}
                 self.observe(act)
-            elif not msg.get('text'):
+            elif (not msg.get('text')
+                  and not (msg.get('image_url') or msg.get('attachment_url'))):
                 # Do not allow agent to send empty strings
                 msg = None