I’ve been using Flickr for a couple of years now, mostly for the library. Since I pay personally for the extras on the account, I also use Flickr personally, to share photos with kids and friends. I use the Flickr uploader to move photos from the computer to Flickr, which lets me designate the “set” they go into.
To use the photos on the library website, I link from the appropriate Flickr set to the matching blog entry. This lets me make photos available on the website without having to do a lot of editing or resizing or using up the website storage space. The drawback is that the photos aren’t viewable on the site itself. I’m still trying off and on to make photos stored on Flickr visible on the site – say, one per linked set – but haven’t been able to make that work yet.