According to your description, I'm sorry, I'm not sure about the specific model and system version of your computer?
Win8 system comes with it? Face ID face recognition login system, if you can't delete photos, you can only delete accounts, re-establish accounts and take photos.
Delete method: log in to the system with the administrator account, open Face ID-Manage Users-Display Account, click "Delete", then re-establish the account and set photos. You can only set the Face ID picture of the current login account.
I hope the above information can help you, thank you. If the above reply still doesn't help you solve the problem, you are welcome to continue asking questions, or you can log on to ASUS online instant service: /support/? Further consult the engineer, thank you for your support and attention to ASUS, and wish you a happy life!