Sharing my blog posts on Facebook

I am attempting to gain exposure to a blog post on my website collegeknowledgeinc.com. I added the plugins for posts to be shared on facebook, however, whenever I am about to share the link to the post, the thumbnail comes up but shows the picture as being blown up. Is there any way for me to get the thumbnail pic to fit within the frame?

here is the link to the post, let me know if you are having the same problem and if so, can you assist me in fixing it? Much appreciated.