Problem in Attach the Link in Fan page at facebook!

hi friends

i have created the fan page in facebook,
http://www.facebook.com/pages/smashinghub/341206239007

whenever i placed my website link in fan page, it’s does not show the image, it only show the description and title.
smashinghub.com is my website

what is the problem?

whenever i placed the other website links, it’s shown properaly . but when i placed from my website, it shown the problem
plz guide me