如果有多个收件人，通过跟踪像素图像来提交邮件，如何知道谁已经打开了邮件[关闭]

I have build a tracking system by pixel image , but I am unable to which email has been opened , if more than one recipients are in To or CC fields .

this is my tracking pixel image :

<img src="http://xpn.com?pxl=787383-33ui3u3i3-11111 />

Please suggest how I can achieve.

You can't track an email send to multiple people, you will have to send each an email with a custom pixel with an id or hash to identify the user that you sent it.

<img src="https://trackingDomain.php?e=user@email.com" >

<?php

// please validate this, just as a request for demo purposes.
$email = $_REQUEST['e'];

// update database.
$query = "Update sentEmails set readed = 1 WHERE email = '$email' ";
//....
/// database logic etc.
//....
?>