Open email tracking doesn't get tracked

Emails are being tracked by a tracking pixel. This is simply a 1 pixel GIF image in the source code of email messages sent by Mautic. When an email is opened by an email client like Outlook, Thunderbird or GMail, the client tries to load the images in it. The image load request is what Mautic uses to track the email open action.

Some email clients have auto loading images disabled, and users have to click on a "Load Images" button to load images inside an email message. If the images aren't loaded for this reason or another, Mautic doesn't know about the open action. Therefore, email open tracking is not 100% accurate.