Why can't I delete photos from my mobile phone album?

If you use a vivo phone, you can view the photos of the phone and you can't delete them. How to do this:

1, restart the phone;

2. Enter Settings-System Upgrade. IQOO (Monster) UI version /Funtouch OS9.2 Some models need to enter the Settings-My Device-iQOO (Monster) UI version /Funtouch OS version detection and update system;

3. After data backup, enter Settings-Applications and Permissions/More Settings-Application Management-More-Display System Flow-Find Album-Store-Clear Data.