Using the My Profile menu (displayed in the top right of the Cloudbrief interface), you can upload a custom avatar for your user account. This is not required, however it can make looking at brief permissions easier if your staff have easily recognisable avatars loaded.
An avatar can be any JPG file (less than 200kb in size). For best quality, you should use a square image if possible. It will be automatically resized to the correct dimensions when saved.