You can tag people in the pictures in the gallery or taken via camera on Android phones and tablets. If you tag picture on Galaxy S4, then you can create album story based on the tagged people. To start tagging pictures do as follows:
1. Open Camera app and take a picture, and then view it(Or simply go to Gallery and choose one)
2. If the phone identifies a face, a Yellow Box appears around the face. (You may need to turn Face Tag on, by tapping Menu button and choosing Face Tag option)
3. Tap the recognized face, and select "Add Name"
4. Now, the "Contacts" App is opened and you need to assign a contact to the tagged face.
** The phone suggests the contact name, if you have already tagged him/her.
Note that, if the phone doesn't identify some faces, you need to do it manually. Tap and hold your finger on the screen (while seeing the photo) and wait to go to "Tag Face". There you need to move the Blue Box on the face, and hit Save.
Read More Galaxy S4 Tips and Tricks