I thought that too, but no. It seems it replaces the original link with a google url, which is basically a proxy address for that original url. It seems they ma

I thought that too, but no. It seems it replaces the original link with a google url, which is basically a proxy address for that original url. It seems they may cache it, but don't preemptively download it when the mail is received. http://gmailblog.blogspot.com.au/2013/12/images-now-showing.html http://gmailblog.blogspot.com.au/2013/12/images-now-showing.... Obviously if they downloaded any image linked to an email send to gmail that could lead to a DOS, and be very wasteful in any case. So they wait until you actually open the email. But at least it obscures your IP unless you click on the links.