Facebook share doesn't display the right image

[Taieb BACCOUCH]

Hi, am using joomla 2.5.14 and k2 Version 2.6.7 as a content manager. Am also using http://www.addthis.com/  to share the articles. When i try to share an article everything works fine with all social media like google plus, twitter, etc. But i have a problem only with Facebook share button. It displays the wrong and the same image everytime. You can find bellow the a screen shot of the popup window : 
How can i fix it? if you need website access, plz contact me in private. Thank you.