Originally Posted by
docbert
It's still causing pain for marketing/tracking images, because although they can tell you opened the email, they are not seeing many of the details that are normally visible (user agent/device time, IP address, etc).
The IP is useful in determining geographic location, I'm guessing?
So if Google caches the image, Google can now track who is opening emails, and they, not the advertiser, now have the location info? Smart.