Gmail automatically downloads images ahead of time, so the tracking pixels will have been fetched by Gmail themselves regardless of when the user opens the email.

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ChicagoBoy11 2 hours ago | parent | next [-]

I had a demo for some high-school students for an ethics and tech class that successfully demonstrated these with a GMail account, so when this started happening I got very upset lol.

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extraduder_ire 31 minutes ago | parent | prev | next [-]

I think gmail adds some heuristics on top of it, like if the same image was included in emails to multiple people.

At least that's what I remember from them announcing the feature. No idea about other providers, and I haven't tested the feature myself.

	▲	danaris 5 minutes ago \| parent [-]
		With a proper personalized tracking pixel, a simple deduplication won't catch it—the whole point is that each email's tracking pixel has a unique URL that lets them know that you opened the email. It is, of course, very possible that Google has heuristics that can catch tracking pixels—in fact, I would go so far as to say that if they chose to, they 100% could, probably tomorrow. But given where Google makes its money, I would not in the least trust them to do that for me.

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jdhawk 37 minutes ago | parent | prev [-]

So does Apple's Mail Client. So do most webmail providers. Open signals are generally worthless.