Hi Mark,
I openede this ticket because I have still issues suing the CDN fetaure of ES. If I activate the server and client functionality there seems to be somee issues regarding photo upload (activity box and photo page). I tried using the plugin NoNumber CDN for Joomla and JOMCDN. They seem to be the same one - JOMCDN is a paid one and has more features....
I also tried MAXCDN and Amazon S3 with Cloudfront and the issue is still the same. Now I would like to use the Amazon product.
Attached you will find my access data...
Thanks for your support!