Flagrant Flickr promo, but if you're a charity who can see the benefit of have a few people given a free Flickr pro account then why not take advantage.
Thanks Hugh, for flagging this. It's ceratinly worth exploring. But, as you mention, a group must be formally registered as a charity to benefit. And, if I'm reading it right, there are also a couple more conditions which need considering.
■ The Pro accounts can't be re-assigned from named individuals - even if they leave the charity.
■ The recipient organisation "must be willing and able to provide information to Flickr for the purposes of creating a case study or testimonial on this programme". Which may be no more than what a charity does anyway, to advertise itself. Or it might be more work.
For most people, the free Flickr account is all they need. The Pro account costs US$25 p.a. (Currently about £16.) So the real question is whether the extra work involved is worth it.