How to share photos with specific people
1. Upload photos to a folder in your Google Drive.
2. Go back to the top level of your Google Drive and check the box next to that folder and click "share."
3. Click the main sharing settings (where it says "private") and change to "Anyone with the link."
4. Email the link to students, parents, etc. They will be able to access it without having to log in. Add or remove photos from that folder as you see fit; you do NOT need to re-send the link each time.
For details, watch (in full-screen to see detail) the 3-minute screencast below: