Open "Contacts" app :
- select a contact,
- tap on (Edit contact),
- tap on ,
- choose or take a photo,
- select a picture,
- resize or crop if needed,
- tap on "DONE" or on "OK" to confirm,
- tap on or on "SAVE".
Click here to know how to associate a picture with a contact using "Photos" app or "Gallery" app (Y51, Y61, Y81).