Opengraph meta tags for image in contao pages

I need to display meta tags as html source. For this, I extended the page template fe_page and wrote the meta properties there. I need to have the opengraph meta tag properties. I implemented the following:
<meta property="og:site_name" content="{{page::rootTitle}}" />
<meta property="og:title" content="<?= $this->title ?>">
<meta property="og:url" content="{{env::url}}/{{env::request}}">
<meta property="og:description" content="<?= $this->description ?>">

These all works. Now I need to have the property "og:image" for my contao pages. But for contao pages, there is no field present for image upload. Can we have "og:image" meta tag for contao pages. If so, how this can be achieved in my page template fe_page for contao pages?

See my answer to your question here: https://stackoverflow.com/a/47075695/374996