Implementing a photo library with WP

Hi .. Having retired form the IT industry, I’m now the Website/IT volunteer for a global dental (i.e. oral health) charity. I’ve built a website for WP with which they are very pleased, but the latest challenge is to implement a library for their several thousand photos which they have taken at many projects around the world. We have a mass of unused server space so, rather than keeping them locally on a windows server box, it would be good to store all these photos in the cloud where they can be accessed by any employee or volunteer of the charity when creating posters, newsletters, new web pages etc. The photo library would have to be password protected and allow a user to see photos in thumbnail and full size with date taken, size etc and stored/viewable in various categories. Charity staff could then download the photo ideally in a specified resolution so that further downsizing would not be required.

Could this be done as maybe password protected pages within the main WP site ? I see that there a load of ‘Gallery’ plugins e.g. Nextgen but these seem to be oriented towards presenting a web user with a defined set of photos rather than the more practical use that the charity are looking for.

Don’t want to do this by giving wp-admin access to all charity staff so must be done ine way or another via the front-end WP interface. This probably means that the WP Media library can’t be used for this application. Guess that I’m looking for a sort of cloud-based Picasa or maybe I should be using Flick-R rather than building something into our WP site.

Any advice most welcome
Thanks
Ron