When I share an article with a URL into the newsfeed it shows the image at 560x292 like I want it to. However, if someone clicks Like within the same article and chooses to "post it to Facebook" it shows up as a thumbnail. Here's a link to the FB debugger
Here's the link to the website in question: http://smartergovernmentwa.org/
Before posting this I enabled the debug info and cleared the site cache.