Creating a large photo archive for members only.

I volunteer at a small nonprofit history museum. We have thousands of old photographs that we want to make accessible on our new website in a "members-only" area. Users should be able to filter, sort, and search through the photos to find what they are looking for. Photos can also have historical information, i.e., time period, detailed description, etc. What is the best way to accomplish this goal? Can this be done in Squarespace, or is there a plug-in or third-party service that needs to be linked to our website?