Cannot get thumbnails when I share pages on Facebook

Hi,

I have finished designing my website, but I have a problem. Whenever I share the page or any article on the website on facebook, I do not get the thumbnails or the title of the article on the share screen. I did code the meta tag and link rel tag. Tried hard coding the values to image on my gallery, but nothing works. Appreciate any help here!

Here is the link to the article I want to share: https://picsbynik.byethost9.com/2012/05/22/photography-basics-for-absolute-beginners/
and here is a part of the HTML output of the website:

<meta name="generator" content="WordPress 3.3.2" />
<link rel='shortlink' href='https://picsbynik.byethost9.com/?p=56' />
<meta property="og:site_name" content="Nikhil Unnikrishnan Photography" />
<meta property="og:type" content="website" />
<link rel="image_src" href="https://picsbynik.byethost9.com/wp-content/uploads/2012/05/Blog_article_thumbnail.png" />
<meta property="og:image" content="https://picsbynik.byethost9.com/wp-content/uploads/2012/05/Blog_article_thumbnail.png" />
<meta property="og:title" content="Photography Basics for Absolute Beginners" />
<meta property="og:url" content="https://picsbynik.byethost9.com/2012/05/22/photography-basics-for-absolute-beginners/" />

The share button does work on the page, but even that does not display an image thumbnail or article title. I tried googling, but nothing worked for me. Please help me out here if you have any ideas.

Regards,
Nik