Email tracking pixels: what they reveal and how to limit them
Learn how remote images can signal that an email was opened, what Dayfly Mail blocks, and why links and temporary addresses have different privacy limits.
Maintained by Dayfly Mail · Updated
A tracking pixel is a request for an image
Some HTML emails contain a tiny image whose address points to a remote server. The image may be invisible or easy to overlook. When a mail reader requests it, the server can record that request; a unique image address can associate it with a particular message or recipient.
An image request is a signal, not proof that a person read or understood the message. Depending on the mail client, proxying, caching or automated scanning can also affect what the sender observes.
What a sender may learn
If a mail reader connects directly to the sender's image server, the request may disclose a time, an IP-based approximate location and information about the requesting software. Some mail services fetch images through a proxy, changing what the sender can see. A unique image address can still help identify the message.
Mozilla describes why Thunderbird blocks remote message content by default. Gmail offers a setting to ask before displaying external images and explains that senders may sometimes know an image-containing message was opened.
How Dayfly Mail handles images
In the public Dayfly mailbox, the HTML message viewer blocks remote images and other external content. Images embedded as supported data URLs can still appear. This means a remote tracking image should not be requested simply because you open the message in that viewer, but it also means ordinary logos and illustrations may be missing.
This protection concerns the message viewer. It does not mean the sender never delivered the message, that your activity elsewhere is hidden, or that every possible tracking method is blocked.
Opening an image and following a link are different
A link can contain its own identifier. If you follow it, the destination site may record the visit, even when the mail viewer blocked remote images. A temporary address also does not hide that address from the person or service sending the email.
Treat unexpected requests for passwords, payment details or urgent action with caution. When in doubt, open the service through a known address instead of using the link in the message.
| Action | What to keep in mind |
|---|---|
| Open an HTML message in Dayfly | Remote images are blocked in the public mailbox viewer; some message images may not appear. |
| Follow a link in the message | The destination may receive a request and an identifier contained in the link. |
| Use a temporary address | It separates the task from your regular inbox, but it does not make the sender or website unable to identify the address. |
| Read the message in another mail client | Its image settings and proxy behavior may be different. |
If you are testing your own email
A missing remote logo in Dayfly can be expected behavior, not necessarily a broken HTML template. Check text and layout here, then use the intended email clients and their documented image settings to test how recipients will see the design.
Use test messages and accounts you control. Avoid sharing mailbox access links, verification codes or personal information when reporting a rendering problem.