The Facebook mobile apps have a Profile Picture login feature that lets you log in to the Facebook app by just tapping on your profile picture.
Here’s how. Facebook offers to enable Profile Picture login when you sign out of the Facebook app, or when you delete it from your phone and install it again.
Once you’re past the login screen, it will offer to turn it On. If you don’t feel like going to all that trouble, open Facebook from your desktop.
Click the little drop-down arrow at the top right and select ‘Settings’.
On the Settings page, select ‘Privacy’.
Scroll all the way down and you will see a setting called ‘Profile Picture Login’.
Expand it and click the listed device(s).
It will remove the profile picture login for that device only.
If you’ve used it on multiple devices, you will have to remove it for each one.
Profile Picture Login makes logging in much faster after you’ve logged out. If you reset a device to factory settings or wipe, it will likely remove the device from your Facebook account.
It doesn’t serve as much of a security feature.
If you have profile picture login enabled, and you sign out of the Facebook app, signing back in takes only a tap. You might want to go with the 4 digit PIN option instead if you’re looking for something more secure.