All those obnoxious marketing emails flooding your inbox aren’t just a product. They also keep track of whether you opened the email, when you opened it, and where you were at the time by using software like Mailchimp to embed tracking software in the message.
How does it work? A single tracking pixel is embedded in the email, usually (but not always) hidden in an image or link. When the email is opened, the code in the pixel sends the information back to the company’s server.
Some attempts have been made to limit the amount of information that can be sent in this way. For example, since 2014 Google served all images in Gmail through its own proxy servers, which could hide your location from at least some tracking applications. And extensions like ugly emaile and PixelBlock are developed to block trackers in Chrome and Firefox.
There’s also a simple, simple step you can take to avoid trackers: prevent your email from automatically loading images, as most of these pixels hide in images. You won’t be able to avoid all the trackers that might hide in your email this way, but you’ll stop a lot of them.
Here’s how to disable automatic image loading in major desktop and mobile email apps:
Gmail on the web
- Click the gear icon in the top right corner to access your settings, then click “View all settings.”
- On the ‘General’ tab (the first), scroll down to ‘Pictures’.
- Select ‘Ask before showing external images’.
- Scroll down to the bottom of the page and click “Save Changes.”
Note that this also disables Gmail’s dynamic email feature, making emails more interactive.
While the browser-based version of Outlook doesn’t let you stop images from loading, you can make images load through its own service. To enable that:
- click on “Settings” (the gear symbol in the top right corner). In the column that opens at the bottom, click on “View all Outlook settings”.
- Select General > Privacy & Data.
- Scroll down to ‘External Pictures’ and select ‘Always use the Outlook service to load pictures’.
Microsoft Outlook (Office 365) for Windows 10
- click on “File” > “Options”.
- In the ‘Outlook Options’ window, select the ‘Trust Center’ option.
- Press the button “Trust Center Settings”.
- Check the boxes with the label “Do not automatically download images in standard HTML emails or RSS itemsitem” and “Do not download images in encrypted or signed HTML emails”. You can make some exceptions to the first item if you want by checking the boxes below.
Microsoft Outlook (Office 365) for Mac
- Go to “File” > “Preferences” > “Read”.
- You can choose to automatically download images only from trusted contacts, or to disable all automatic image downloads.
- Select Mail > Preferences.
- Click on the tab “See”.
- Uncheck the ‘Load external content in messages’ box.
Gmail for Android
- Tap the three lines in the top left corner.
- Scroll down and select ‘Settings’.
- Tap the email account you want to configure.
- Scroll down and select ‘Pictures’.
- Tap on “Ask before showing external images”.
Gmail for iOS
- Open Gmail for iOS, tap the hamburger menu in the top left corner and scroll down to Settings.
- Tap the account you want to personalize and tap Pictures.
- Switch from “Always show external images” to “Ask before showing external images”.
Apple Mail for iOS
- Tap Settings > Email.
- Find the ‘Messages’ section and uncheck ‘Load Remote Images’.
Another option is to use an email client like: Thunderbird, which blocks external images by default; the application allows you to download embedded content on an individual basis, or allow images of contacts you trust not to send hidden code in their images.
Update July 3, 2019, 3:47 PM ET: This article has been updated with additional information about email clients.
Update September 3, 2019, 7:35 PM ET: This article has been updated with instructions on how to disable automatic image loading in Gmail for iOS.
Update February 17, 2021, 5:30 PM ET: Instructions for Microsoft Mail have been removed and some instructions have been updated.
Update June 11, 2021, 8:00 AM ET: Instructions for Outlook.com and Outlook for Mac have been added and some other instructions have been updated.