If you want to add photo in your friend’s profile, you need to tag them in the photo. “Tagging” someone means that you acknowledge them in the picture. After you upload the picture, in the lower *right* hand corner you will see some links. Click the “Tag This Photo” link. Then click on the face of the person you want to tag.
You can either type in the name of the person or check the box next to their name from the drop down menu that appears. Click the blue Tag button at the end and you’re done! That photo will now show up on the profile of the friend you tagged. Check it