Display messages images

lib/models/conversation_message.dart

@@ -23,6 +23,9 @@ class ConversationMessage implements Comparable {
         assert(message != null);
 
   DateTime get date => DateTime.fromMillisecondsSinceEpoch(timeInsert * 1000);
+  bool get hasMessage => message != null && message.length > 0;
+  bool get hasImage => imageURL != null;
+
 
   @override
   int compareTo(other) {