We wanted to set up one of the links for pictures that classmates might have of our school years. Can they post directly to the link or do we, as administrators, have to do it for them?

Only Admins can edit Customizable Links pages. I'd suggest one of the following:

1) Create a threaded forum specifically for this purpose. It's a nice way to share photos and discuss them at the same time.

2) If you want to control the page alone, set up a threaded forum for picture posting, then save the images and include them on your own Customizable page.

How do I do that?

1) Click the User Forums link at the top of your site
2) Click the Add/Edit Forums text link
3) Follow the directions on screen to set up your forums