It seemed to be random. I had been adding the photos and updating the posts over the past two weeks and all were done the same way and were .jpg files. About half weren’t showing.
We have a couple cache plugins, WordPress SEO, ziplist, hreview, Twitter Facebook Social Share, Pinterest “Pin It” Button (for using on select pages only – it wasn’t live on any of those posts), WP-PageNavi, and a couple for redirection and links.
