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by seedless-sensat 1838 days ago
My impression is that Gmail prefetches ALL email images, and then serves them to the reader via their CDN. (Checking a random email in my inbox demonstrates this, https://ci3.googleusercontent.com/proxy/...)

As a result, I thought there was no signal for tracking pixels? I might be wrong though
1 comments
neolog 1838 days ago
They know when google loads the image, which is when you open the email.
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spicybright 1838 days ago
They only know when google fetches the image, which can be any time between you receiving it and opening it. I highly doubt it's on the fly right when you open it.
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snowwrestler 1838 days ago
It is in fact on the fly when you open it.

All Gmail does is proxy the request to hide your IP from the server hosting the image file. Gmail does not change the timing of the request, the URL, or the image file.

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