Is there a way to just have ONE library for all my photos, and have a sub-library for each album? Same for videos. I have several libraries, one for each family vacation and my library list is getting out of control. Can we just have one HOME MOVIES library, and when you click it it shows you Sub-Libraries?
If your folder structure looks like this:
If you set the folder for you Photos library as shown, the Library will mimic your folder structure when viewed in Photos mode. Same for Videos. Of course, now you’ll have to go to Yosemite, Grand Canyon, Alaska, and Mt. Rainier… 
You can also add multiple folders to your Library setting:
Thanks for the tip, beckfield! Same problem solved here.
