Relevant Product: Signature Manager Office 365 Edition
Scenario
You wish to create an Outlook Web Access (OWA) policy however, all of the images are displaying as below
Cause
Outlook Web Access does not support embedded/inline images in email signatures. This applies to all versions of OWA.
Resolution
The images must be hosted on a publicly accessible website. Once the images is hosted online, insert the image URL when inserting an image in a signature template.