Turn off automatic loading of images in windows 10 Mail
Yes there is a way to do this in the email app on Windows 10
go to Settings> Account> Change mailbox Sync Settings> Uncheck " Always download full message and Internet images"
Unfortunately Microsoft at every update seems to change how their programs work modifying settings, UI, and adding confusion...
I still had the same issue (April 2019, Windows 10 1809) 'till I finally found a "hidden" setting to enable/disable the automatic image downloading in Mail:
Settings (gear icon) > Reading pane > External content > Automatically download external images and style formats except S/MIME Mail = OFF
N.B.: of course you can still manually download the full message and images clicking at the bottom of every mail on the small placeholder "Download message and pictures"
To say the least, you can't.
I just tried like my life depended on it to figure out how it could be possible but I think this statement sums up the Windows 10 mail app:
... (the) Windows 10 Mail has bugs and features that should be included but aren’t. Frustratingly, some basic but useful parts of Windows 8.1 Mail were stripped out in this new version.
Windows 10 Mail: Beautiful but bug-ridden
However, in the event you switch to something like Outlook 2010 or 2013 you can still do it there.
Outlook File menu
Options then Trust Center
Trust Center Settings
Automatic Download: mark the box that says “Don’t download pictures automatically in HTML e-mail messages or RSS items”: