PSA: (a) Disable automatic loading of e-mails in Gmail if you don't want to be tracked. (b) Don't ever click links from e-mails, Google for the content instead.

PSA: (a) Disable automatic loading of e-mails in Gmail if you don't want to be tracked. (b) Don't ever click links from e-mails, Google for the content instead. Settings -> General -> Images -> Ask before displaying external images (I've also been debating sending an auto-reply back to users of such e-mail apps (e.g. Superhuman) with an autoresponse to the effect of "Due to the use of tracking pixels your e-mail has been de-prioritized. If you would like a faster response please send me a plain text e-mail" to discourage people from using these privacy invasions.)