If you have an individual in your tree that is tagged in more than one photo and you want to change his personal photo in the tree to one of the other photos in which he is tagged, take the following steps:
1. Select Tag people from the Photos tab.
2. Click on the Show all link in the top right corner of the screen.
3. Type the name of the relevant person in the input field.
4. Click on the name in the list and choose ‘Change personal photo’.
Choose the relevant photo, and click OK.