Add galleries for groups. Click on default logo image to enter/view it.
Group admin decides if users or only mods/admins can upload.
Images optionally viewable only to group members. Uploader selects privacy level, group admin can decide if all images are group only.
Bonus points for elegant BBcode & HTML text boxes for users to easily copy & paste to use elsewhere. Maybe a nice CSS dropdown upon hover or click.
Site admin sets max file size, dimensions, and quantity allotted to each group..