> Clarified that the image server cannot see where the request came from. It may still be able to determine who the request came (ie email address validation) i

> Clarified that the image server cannot see where the request came from. It may still be able to determine who the request came (ie email address validation) if the image URL has some kind of tracking data in it. They will know if the mail reached or not, but they will not know if the mail was opened. Because, it is possible that you never open the mail but the image is still downloaded to the fastmail server.