Get a page in a social network "Classmates" either sign it, if you already have a username and password. Add to your profile pictures which you want to tag a friend. This can be done in several ways. If you already have previously downloaded photos go to "Photo". Uploaded photos can be sorted in different albums or be in one called "Personal photos". If your profile has no photo, click "Add personal photos" on the main page. Go to the page on which you want to upload images, and click "Add photo" or "Add photo to album".
Specify the path to one or multiple photos on your computer's hard drive and upload them to your social network profile. After that image will appear in the appropriate albums. Click on the desired photo to enlarge it. In the left part of the page a menu will appear, one of which is called "tag friends". Click on it. On the pictures mark the area which shows your friend, then select his name from the list. In the same way you can tag multiple people in one photograph.
After you mark the person in the picture, it will receive an automatic notification about this and maybe how to save the mark and delete it. If the mark of each photo does not appear for a long time, write to him and ask to view the incoming system notification.