What's your role? Network Creator (NC) or Admin?
Tell us a bit about your network (example: Creators is a community of Ning Network Creators who gather together to collaborate, troubleshoot, and share tips and tricks)
Former NC now using BuddyPress/WordPress. I learnt a lot here back when I first starting working with websites, kinda miss the place so check in pretty regular to see what's going on.
You've somehow set this as your main site background image. I've not used Ning for a while but I suspect it's easy enough to remove it in your settings.
As a temporary fix while you work it out add this to your custom css:
I remember when creators was blessed with posts…"