Return better blank gravatar image

services/web/app/views/project/editor/chat.jade

@@ -23,7 +23,7 @@ aside.chat(
 					div.date(ng-if="$index == 0 || (message.timestamp - chat.messages[$index - 1].timestamp) > 5 * 60 * 1000")
 						{{ message.timestamp | formatDate:'h:mm a' }} {{ message.timestamp | relativeDate }}
 					span.avatar
-						img(ng-src="{{message.user.gravatar_url}}")
+						img(ng-src="{{message.user.gravatar_url}}?d=mm&s=50")
 					div.message-wrapper
 						.name(ng-if="message.user.id != user.id") {{ message.user.first_name }}
 						.message(