External images and tracking pixels

Last updated October 2026

Many emails do not carry their images along but load them from the sender’s server. That is more than a technical detail: the fetch tells the sender that, when and on which device you opened the mail. Newsletter providers embed invisible one-pixel images for exactly this purpose, so-called tracking pixels.

Which is why YouniqMail blocks external images by default.

What you see of it

Where the images would be, the mail stays blank, and at the top of the mail a notice tells you how many external images were blocked. Load all fetches the images for this mail. One click, and the mail looks as intended. You decide, though, when the sender learns of your reading.

Show blocked images lists the images one by one. There you load a single image or trust its domain right away.

Background images are blocked too, as are videos and sounds a mail would fetch, and the same goes for the print view. Tracking pixels are also recognized by phishing protection, which points them out in the notice.

Embedded images sent as part of the mail (say the logo in a signature) are unaffected by the blocking, since they reveal nothing, because no fetch happens.

Trusting senders permanently

For senders whose images you always want to see, there are two lists under Settings → Privacy:

• Trusted senders: an address (alice@example.com) or a whole domain (@newsletter.example).
• Trusted image domains: hostnames whose images always load (subdomains included), so example.com also covers cdn.example.com.

The fastest way onto the list goes through the mail itself: the notice about the blocked images offers Trust sender, and the arrow next to it Trust sender domain.

Switch it off entirely?

The Block remote images switch on the same page changes the behavior globally. If you mail exclusively with trusted correspondents, that may be convenient. For mailboxes with newsletters and unknown senders, the default is clearly the better choice: it costs one click per mail and pulls the rug from under silent tracking.

Regardless of this switch, YouniqMail loads the brand logo a sender has published via BIMI. It comes from the address the sender specifies for it. YouniqMail requests it at most once every 30 days per domain, so the fetch reveals neither a particular mail nor whether you opened it.

What else YouniqMail contributes to privacy, and what leaves the device at all, is covered in Which data lives where?.