So I am trying to change the way my sender icon shows to our customers, editing the sender identities don't have any effect. We are using roundcube. All you see as a sender icon is a "?" which is really not professional.
It is not possible. You can add a profile picture to be shown to Gmail users. By creating a Google account for your email. This can be done at https://accounts.google.com/signup/v2/webcreateaccount?flowName=GlifWebSignIn&flowEntry=SignUp