Marketing emails still send unique URLs for each recipient so they can associate your email address with opening any images and links. Google's proxy doesn't remedy this.

https://arstechnica.com/information-technology/2013/12/gmail...

Google can still track you, but if you really care about that then you're probably not using Gmail anyway.

[0]: https://gmail.googleblog.com/2013/12/images-now-showing.html

I just installed a fresh copy of Office 2019 in a vm and Outlook's default setting doesn't load images. This block-downloading-images-default behavior matches what I read here: https://support.microsoft.com/en-us/office/block-or-unblock-...