UPDATED: A compatriot solved it. Yes, it had to be https. We did that and republished. We also had to get the Facebook debugger to rescrape our site.
I read somewhere that if I took this bit of code from someone else's post and substituted our website's URL and the information about the photo in our header. Is there anything anyone can spot that I've done wrong? (I see it should be https, but would that make it not work?). I put the code in the header on our SEO in settings and also on the landing page, just in case.
<meta property="og:image" content="http://www.betterangelscentraltexas.org/uploads/1/2/6/4/126411993/background-images/450483083.jpg" />
