I never figured out how to stop it from scraping any images in the sidebar so I just removed the images from the sidebar. I started using the SEO Yoast plugin which seemed to help to pick the right images, however, if I recall correctly even though I had that plugin going, facebook still wants to grab the images from the sidebar.
It is a bit disappointing no one has responded to this thread with a formidable answer for something that is so common an issue. I’ve searhced around way too much time online trying to find an answer but never came across one that was satisfactory.