With Gmail's recent change to serve all images through a proxy, it appears that it is no longer possible to embed an image that is served up via a
localhost URL. For example, as a developer, I used to be able to send an email to myself with content like:
<img src="http://localhost/trackthismessage?readby=xxxx" />
and, upon telling Gmail to display images, the image would be served up by my local development machine.
Now, with the proxy in the middle, it seems this is no longer possible. Is this functionality now just gone or is there a workaround?