Why can't I add a photo to a contact?
Do you have enough storage available on your device? Try to use the Contacts app to add a photo, or from your Gallery or Photos app see if you can set a contact photo by tapping on "Use as", and selecting a contact.
How can I hide my Viber profile picture from someone?
Make Viber profile photo hidden from unknown users
Having a profile photo on Viber helps your contacts recognize you quickly and easily, but you can just as easily keep it hidden from unknown users. All you need to do is open “Privacy”, choose “Profile photo” and select “Nobody”.