: The Facebook Profile Picture Guard adds a visual shield and prevents the "right-click to save" or "screenshot" functions on mobile devices.
To ensure your own photos remain private and cannot be "viewed" by strangers, you should: Lock your Facebook profile | Facebook Help Center facebook locked profile picture viewer online verified
: They ask you to "log in with Facebook" to verify your identity. This is a trap to steal your email and password. : The Facebook Profile Picture Guard adds a
: Facebook uses secure authentication tokens. If you aren't an approved friend, the server literally will not send the high-resolution photo data to your browser. : Facebook uses secure authentication tokens
: Facebook’s Graph API (the tool developers use) respects all user privacy settings. It will not return private images to unauthorized apps. The Dangers of Using Third-Party Viewers