Site Avatar

My question is about changing Site avatars, which I think you call it Blog avatars. The Avatars plugin isn't an option for me since I'm running Buddypress in the root Site of my Multisite Network. In the list of Sites on my network the avatar associated with the Site is the avatar associated with the Admin's email address. For some clients, tho, they are businesses and they want a logo, not their picture, and for others, they are using a impersonal email and don't have a User account associated with that email, so they receive a Mystery Man avatar. Is it possible to change the Site avatar in Multisite or do I need to find a plugin somewhere?