Hi Claire
We use Pixevety and have done so for a few years now with great success.
From time to time we publish galleries internally for parents but students dont have access to this gallery.
Students can create content but we upload this via Schoolbox (intranet) so its not widely shared. Same for staff but this can be a minefield.
Come for a visit and I can show you how we use Pixevety if you like. Steve