A quick google search later and I found out that the size of the photos included on your website must be a minimum of 200 pixels by 200 pixels to qualify for display by Facebook. Huh! Who knew?! When I took a second look at the photos on my website they were indeed too small. A simple resizing to make them bigger was all it took to fix the problem. Voila!
*Remember that you can always make a photo smaller but sometimes if it's too small to begin with it will become very blurry if you try to make it bigger.
Next you will also need to check the size of your photos directly in your web builder. In this case my services photo is 285 pixels by 191 pixels. Facebook is unable to recognize this in my posts because the 191 pixels does not meet their 200 pixel minimum standard.
As an additional note, Facebook also has a “Debugger” site that will evaluate your website and can run a diagnostic to see if there are any problems with it. The debugger also caches information about your website. So if your photos need to be refreshed, you can clear the cache and tell Facebook to find new pics from your website. You can then even choose a default one.