Facebook share not pulling preview image

I’m using a slrlounge template and facebook is not pulling up a preview image when sharing a link (either directly or through the facebook share button at the bottom of the post).
I’ve tried adding meta tags as directed by facebook with no luck. I may be doing this incorrectly.

The only thing that shows is the website address in bold and then the direct post link below.

I am new to HTML and having a hard time finding and understanding the fix!
Any suggestions are MUCH appreciated!
TIA!