a girl picture shows in place of any supposed picture in the website I visit

Hi,

 

It has been few days when I visit a page on the internet lets say http://ca.yahoo.com, when I scroll down I see a girl (laughing) picture in place of any other supposed picture(s) in the site.

To me this must be a virus but I updated my NIS for Mac and scanned the entire system, nothing showed up!!!!

 

Any similar experience from someone else??  Any remedy???

I'll appreciate your response.

 

Thanks!