I came to say this. Ideally, my computer would do what I want and only what I want. This doesn't always work out, such as in the cases of multiple users or malware, but it's an ideal we should strive for.

I classify any case of a computer that's solely mine doing something I don't want as either a bug or malware.

Email clients block HTTP images for a reason. That reason is so that people can't use them to implement read receipts.