Pixel tracking

[CaptainColin]

Pixel tracking is when someone includes in an email a small picture, even 1 pixel wide that includes code that is executed when the picture is displayed. You don't need to do anything except open the email. The sender can then see information from your email client about the device you are using when you opened the email, your IP address, and lots of other information. There are a few email clients that block Pixel tracking, such as Hey, but Aqua mail doesn't. Search on Google for more details.

[Justin]

You can disable loading external images automatically.

[arf8]

To provide a little more context, the level of information being collected is not as intrusive through email as a webpage, for example they can't get your IP through email alone.

Also if you are using a provider like Gmail, Outlook, GMX etc..., they already run all emails through a image proxy servers that filter out all the trojan pixel trackers.

You have to understand you are foregoing some level of personal information the moment you connect to the internet if you don't know how to obfuscate yourself using various tools which is overkill for the general population.