> If I'm concerned about privacy, I don't turn on loading images by default

The point is that you shouldn't have to do this, and can be afforded the same privacy while improving your user experience.

It can’t though. Whenever the image is loaded, by default or otherwise, the image itself can act as a read receipt. That’s how most email services track opens. If the server downloads the image for you, then the server has to store the image to prevent you from accessing it directly from the host. That creates cache time discussions, storage quote discussions, etc.

Even if the image itself is proxied through a CDN, the time the image is accessed is still exposed.

> That creates cache time discussions, storage quote discussions, etc.

why cache time discussions, after initial download there is no need to download it again, email is not the browser, there is no expectation that the image in email will be the actual at the time of opening, the expectation is that the image is actual at the time of sending. and for storage you can use hash to not store duplicates, and probably save bandwith with optimization.

True. I was mostly thinking of Proton as a browser based service. Browser cache would cover the same case.

They do have the Bridge now to use it on the desktop.

> Even if the image itself is proxied through a CDN, the time the image is accessed is still exposed.

So have the mail server download the image immediately upon getting the message, so that the timestamps (and boolean of being accessed) means nothing?

plus those who "need" to embed visible images (e.g. marketing insisting on the company logo in the footer) could use svg data uris now, so they're not really in conflict with blocking 3rd part content.