:When a browser loads a profile picture, it fetches a long, encrypted URL from a domain like fbcdn.net . These URLs are temporary and often include a timestamp after which they expire for security.
When you upload a profile picture, Facebook doesn’t just keep one file. It creates dozens of different resolutions, ranging from a tiny 32x32 pixel thumbnail (used in chat windows) to a massive 2048x2048 pixel file (used if you click on the photo to expand it).
Facebook does not allow users or third-party apps to track who has viewed a profile or a specific profile picture. Any website claiming to be a "Facebook Profile Picture Viewer" that asks for your login credentials should be treated as a security risk [0.5.7]. Use Cases for Profile URLs facebook profile picture viewer url
Chasing these fake URLs isn't just a waste of time; it is a severe security risk.
Tracking every single view of every single profile picture for 2.9 billion users would require petabytes of storage. For comparison, Facebook only tracks views on video content (for ad revenue) and Story content (which is ephemeral). There is no monetary incentive to store a permanent log of who looked at a static JPG. :When a browser loads a profile picture, it
can return a JSON object containing the direct link to the high-resolution file. Stack Overflow Finding the Necessary Profile URL
Every user has a dedicated album for profile pictures. It creates dozens of different resolutions, ranging from
https://graph.facebook.com/user-id/picture