Here is an article explaining gmail new caching of images. http://blog.mailchimp.com/how-gmails-image-caching-affects-o.. http://blog.mailchimp.com/how-gmails-i

Here is an article explaining gmail new caching of images. http://blog.mailchimp.com/how-gmails-image-caching-affects-o.. http://blog.mailchimp.com/how-gmails-image-caching-affects-o.... Tracking still works and this extension is useful as long as you trust the author.