Originally Posted by
Loren Pechtel
But that request will be made when the mail arrives at Google, not when the user reads it. Thus it doesn't actually tell them anything useful other than it's a valid address (and Google might be fetching the images for invalid addresses just to defeat even this.)
That's actually a good point. So the user will still be identified, but perhaps that's all. And it seems like that might happen anyway, regardless of the image load setting I posted above, if Google is precaching images from incoming mail.