There are several reasons why people might lock their profiles on Facebook:
The only officially supported method is to send a friend request to the user to gain authorized access. fb locked profile dp viewer hot
If you see a locked profile, especially one acting suspiciously in local groups, keep these safety tips in mind: Lock your Facebook profile | Facebook Help Center There are several reasons why people might lock
Viewing a locked Facebook profile picture (DP) in full resolution is technically restricted by Facebook's privacy settings to protect users from unwanted scrutiny and identity theft and full-sized profile/cover pictures.
When a user locks their Facebook profile, they restrict non-friends from seeing their photos, posts, and full-sized profile/cover pictures.