If you need to see someone's profile picture clearly, rely on official methods rather than third-party websites.
Check the profiles of mutual friends. Often, a private user might appear in public photos or in the comments section of a mutual friend’s post. How to Protect Your Own Facebook Profile facebook private profile picture viewer online
Providing your login credentials can lead to your account being hacked. If you need to see someone's profile picture
Facebook Private Profile Picture Viewer and locked profile ... - Blog How to Protect Your Own Facebook Profile Providing
to see if the small, public version of the profile picture appears on other public social media platforms like LinkedIn or Twitter. How Users Protect Their Own Pictures
: Claims to let you view the photo without notifying the profile owner or appearing in any "viewed" lists. Warning: Risks of Third-Party "Viewers"