Linked image are not displaying properly on Outlook 2016 Signature which is running only in Windows 10. I have the same thing happening on more than on computer(Win10+Outlook2016).
As you could see below, it should be displaying our company logo and Facebook logo where it shows only a blank thumbnail. However at the same time image will display if I save the new mail and open it from 'Drafts'.
This is only happening to the images in 'Signature' area, I have tested this with different linked images and the result is the same. Please let me know if someone could assist me in this.