Web security experts say explicit images have been flooding the news feeds of Facebook users for the past 24-hours or so -- including photo-shopped images of celebrities like teen pop star /*Justin Bieber*/.
Right now, it's not clear how the images are spreading. But experts say one possibility may be "click-jacking" -- when clicking on a friend's image shares it - in your own feed.
Hackers also may have compromised the accounts of users with weak passwords or tricked people into installing a malicious code.
If you notice such images on your /*Facebook*/ page -- experts say one of the best ways to protect yourself is to immediately re-set your password.