Your business logo appears on your content Journeys and public profile.
The preferred logo image size should be 80px X 80px.
(In case your logo's shape is rectangle the platform support that as well. The displayed area will be subject to the allocated horizontal space).
The appearance of your logo on a Content Journey:
The appearance of your logo on a public profile:
In order to add your logo please go to the below menu:
Account Settings -> Profile Settings -> Image