Facebook thumbnail self hosted thesis themes

Hi,
I wonder if anyone can help. I have recently moved my blog from WordPress to GoDaddy. I am using the wordpress platform in GoDaddy with the Thesis Themes.

I have added a Facebook share button to my posts but when I try and share my posts it doesn’t seem to be showing the thumbnail image, only the link.

It seems to work on this post: http://tryingnottodisappear.com/?p=606

BUT then doesn’t work on others like this one: http://tryingnottodisappear.com/?p=866

I would really appreciate any help please.
My blog is: http://tryingnottodisappear.com/

Thanks
Tracy

The blog I need help with is tryingnottodisappear.com.