Customization asks for password. Password not accepted

[Valtam]

When I go to the "About Me" section and try to change my login image/photo, it asks me for a password to proceed. 

If you're trying to change user 2's photo, you can't, not as a normal user. Think about it, you're logged in as him/her with no sudo rights. Logged in as you, you'll need to temporarily assign them sudo (Lite User Manager) change the photo with them logged in, logout, login as you again and then unassign sudo from user2.