Just got this from school, and I just don't feel like it's a good idea, given that Flickr's been subject to hacks in the past. I wouldn't mind if it was on the school's on server, but uploading pictures to an American-owned social media site, even if they are marked as private, doesn't feel right to me. AIBU?
"Following up on your requests to share more pictures of the schoolchildren, we have opened a private group at Flickr, where we will upload pictures. Parents will also be able to share their pictures taken in and outside school, like birthday celebrations and excursions. To gain access to our private group, you will need to create an account on Flickr..."