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> Emails pixels can be used to log:

> if and when an email is opened how many times it is opened

Can someone explain to me how these work? Do you load remote content from a server so it knows that the email was opened? Does it re-download this image every time it is opened?

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Generally images in emails are linked, and not actually sent with the email. So any time the email is opened, the email client makes a request to the image host, and this request can contain a unique identifier for the recipient.

Some email services will cache the images for a period of time but in many cases it will perform a fresh request each time the email is opened.

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