Problems with Facebook Linking

Hey y'all,

I am having a really frustrating time trying to get Facebook to show a thumbnail when sharing a link through my site. The site I am trying to link to is http://www.jakekiserphotography.com/Photo-of-the-month/.

When attempting to do this through my Facebook page here, I get nothing. Just blank.

From searching the site, I've seen others with problems not getting to select a thumbnail they want, but I've got nothing at all. Unusually, you'll see that elsewhere on my page I have been able to link them without problem.

I've tried to debug through https://developers.facebook.com/tools/debug/og/object/ and receive this error message:

Object at URL 'http://www.jakekiserphotography.com/Photo-of-the-month' of type '' is invalid because the given value '' for property 'og:url' could not be parsed as type 'url'.

That seems to be a problem but I am not savvy enough to understand what it means.

Any help, please?
Thanks.