Facebook recently announced changes to the platform that mean you need to be paying better attention to the back end of your website if you want people to share your content. From here on out if you don’t specify the Facebook Open Graph metadata on each page of your website,  you won’t be able to get Facebook to show the right image for your post and it will pull whatever info it can find. If it doesn’t look good, people may choose not to share it. Open Graph is simply a system set up by Facebook to enable communications with a website. In the absence of Open Graph tags, Facebook looks at other data.