title: October CMS - extend page to have an associated image
body: <p>What are the best and clean possible ways to extend functionality for including an associated image to each page object (CMS page or StaticPage), adding a corresponding upload widget to the page's configuration in the OctoberCMS backend?</p>
  
  <p>(Additionally, and just as an aside: In what way can one add an associated image to a site's theme?)</p>