Go to the contacts, open the contact and go to the edit option. There select change picture and select one from gallery or take a new one from camera.
Vivo has also one-upped Apple by offering a face unlock feature that works incredibly well with raise-to-wake. You just pick up the phone and it unlocks, brilliant and simple, if unsecure.
Speaking of security, Vivo very clearly explains that face unlock is not secure and that, in fact, the feature can be speeded up by further reducing the security standards. Honestly, this is how Face Unlock should have been advertised to begin with.
Vivo V7 vs Vivo V5 Plus
Both the phones have their pros and cons,lets analyze :-
Advantages of Vivo V5 Plus
1.Better Screen Resolution:-More resolution means sharper and crisper screen.
2.Slimmer:-Slimmer devices are easier to carry in pocket and look more fashionable.
3.Has Dual Front Camera:-Dual front camera is useful for certain effects like blur, zoom and wide angle selfies.
4.More Storage Capacity:-More memory allows you to store more songs, videos, photos and install more applications.
5.Bigger Battery:-It can generally last more time.
Advantages of Vivo V7
1.Light Weight:-Light weight devices are easier to hold without tiring your arms.
2.Supports Memory Card:-Memory cards give your device more storage capacity. So you can store more songs, photos and videos.
Verdict - In my opinion, Vivo V5 Plus is better overall performance and price ,if you need light weight and memory card support you can go for Vivo V7 .
You can also compare these devices on 91mobiles