Use v2 of the overview image

README.rst

@@ -26,7 +26,7 @@ Overview
 
 This is a high level overview of the architecture.
 
-.. image:: http://cloud.github.com/downloads/ask/celery/Celery-Overview.jpg
+.. image:: http://cloud.github.com/downloads/ask/celery/Celery-Overview-v2.jpg
 
 The broker is an AMQP server pushing tasks to the worker servers.
 A worker server is a networked machine running ``celeryd``. This can be one or