Saw this comment late, like tl_donson says, yes but it's fairly consistent. So if your open rate drops 20% to 10% in one month, it's probably your fault and not

Saw this comment late, like tl_donson says, yes but it's fairly consistent. So if your open rate drops 20% to 10% in one month, it's probably your fault and not the mail client hiding it. In my experience most people do not block images in emails, and that's the easiest way to tell if someone opened your mail. Even most people who use an adblocker do not block email images.