When you view a photo on another member's profile, or elsewhere on the site, click directly on the photo and you'll see the option to Like it on the right side of the photo viewer. For photos in a community photo album for one of your schools, look for the Like option below each photo.
The owner of the photo, as well as any other members who view it, will be able to see how many times the photo has been liked.
At this time, you can only add comments to photos posted by other members under school community albums. Go to your school page and click Photos on the left, then open an album and click an individual photo. A Comments box will show below each photo.
Note: You can't edit or delete a photo comment after you've clicked Submit. Only the owner of the photo can remove comments.