Our goal is to use the image that a site has chosen for a particular post.
Step 1: In Wordpress: if you have set a featured image, we will use that.
In Drupal, there's a setting in the Contextly controls that lets you determine what image field will be used to specify a "featured image."
In other CMSes, Contextly looks at the specified image in the meta-data format that we've agreed to pull in.
Step 2: If there's no featured image or it is too small, we'll look for an Open Graph tag that has the image to be used for Twitter or Facebook.
Step 3: If there's no Open Graph image or it is too small, we'll look for an image in the body of the story and use the largest one.