Non-friends cannot click or expand the profile picture or cover photo.
: Notes that the feature often gives users an "exaggerated sense of security" even though some metadata remains public.
: Sending a friend request remains the only official and guaranteed way to see a locked profile's full cover and profile photos. Official Facebook Privacy Resources
You will find dozens of websites and YouTube videos claiming to offer a "Locked Profile Cover Photo Viewer 2025." Here is what they actually offer:
Even friends see a slightly limited view, but the main restriction applies to people not on the friend list.