Oh you mean they prefetch unconditionally, thereby removing any information about whether the recipient has read the email (it always appears as if they did) -

Oh you mean they prefetch unconditionally, thereby removing any information about whether the recipient has read the email (it always appears as if they did) - not that they cache it to share between users and make it seem like they didn’t download the image. Agree - they do that. They can’t make it seem like I didn’t download it but they can remove most of the usefulness of the information (it reveals whether the Gmail address is valid I suppose)