Blocking remote images

Remote images are any images in an email that are downloaded from the web when viewing the message, rather than being included as attachments in the message.

You can choose to block remote images by default in Fastmail's web interface or mobile app. This can help your mail load faster, or help you avoid tracking pixels.

Note: Whenever you choose to load remote images, our servers always load the images on your behalf, so the image host still won't know your IP address or browser. (This only applies to messages opened in the Fastmail web interface or mobile app.)

How to block remote images

You can customize how we block the remote content by going to Settings → Privacy & Security and scrolling down to the Privacy section.

Under Remote images, you can select one of the following options:

  • Show remote images - Remote images will always be displayed automatically.
  • Show remote images from senders in my contacts, otherwise ask - If an email comes from a sender that you've added as a contact, we will display the remote images automatically. If the email was not sent from a contact, we will ask.
  • Always ask before loading remote images - We will always ask if you want to load remote images.

If you set one of the "ask" options, messages containing remote images will have a banner at the top that says Remote images blocked to protect your privacy:

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You can click Load images if you wish to see the images in the message. (As mentioned above, our servers always load the images on your behalf, so the image host won't know your IP address or browser.)

Why do companies use remote images?

Companies often keep images and files on their web servers rather than sending them as attachments with the email.

One reason they may do this is because it reduces the size of the email, since the image file is not attached.

Another common reason is that every time an email loads an image from their server, they can be notified that someone is viewing it. They can then use this information to tailor their content and to track how successful their email campaigns are. This is known as a tracking pixel.

Tracking pixels

A tracking pixel, sometimes called a spy pixel, is a remotely-hosted image included in an email. It can be as small as a single pixel in size, making it invisible to the reader. Senders include tracking pixels so they can see that you've read their email. They can also use this as a way to obtain information such as your email client, operating system, screen resolution, and IP address. 

Because our servers always proxy the images, the sender can only ever know details about our hosts, and nothing about you.

Remote images are set to show, but images are still blocked

There could be instances where images still won't load, even if you have set remote images to display at all times. Services can rate limit our requests for the images. This could be due to the security measures that the services have set up. In this case, even if you have set your account to not block remote images, we would still be unable to display the images.

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