Add xml element (SimpleDraweeView) for image attachments.

app/src/main/res/layout/item_message.xml

@@ -54,4 +54,13 @@
         app:layout_constraintTop_toBottomOf="@+id/top_container"
         tools:text="This is a multiline chat message from Bertie that will take more than just one line of text. I have sure that everything is amazing!" />
 
+    <com.facebook.drawee.view.SimpleDraweeView
+        android:id="@+id/image_attachment"
+        android:layout_width="0dp"
+        android:layout_height="150dp"
+        android:layout_marginTop="5dp"
+        app:layout_constraintLeft_toLeftOf="@id/top_container"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/text_content" />
+
 </android.support.constraint.ConstraintLayout>
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