Sometimes you get chat or private messages from your friends or relative whose on Facebook, and accompanied by a link or a photo/video link. However, an anti-virus company has warned, clicking on any link, including thumbnail images can direct potential victims to installing malicious software or to the infected site. Once it happens, Facebookers can have their computer and Facebook account infected and can be a blind slave for any command from the hacker involved.
If you think you are already a victim of this attack, scan your computer immediately with the latest anti-virus software, change your current password(s), update any security settings and remove any unusual applications installed in your computer. It is also recommended that you don’t just click any link even if it comes from a trusted friend. Its better to confirm if s/he really sent you a message with the thumbnail or link in question.