update not found image (#882)

Author: JimanQAQ

ocfweb/static/img/alt404waddles.png

@@ -14,6 +14,6 @@
         height: 1000px;
     }
 </style>
-     <img src="{% static 'img/404penguin.png' %}" alt="404 Penguin" style='height: 100%; width: 100%'/>
+     <img src="{% static 'img/alt404waddles.png' %}" alt="404 Penguin" style='height: 100%; width: 100%'/>
 </div>
 {% endblock %}