title: Facebook 'og:image' property should be explicitly provided, even if a value can be inferred from other tags
body: <p>I am facing problem in Facebook sharing post. When I try to share any post link of my website Facebook black image. I have also fetch data from Facebook debugger and found this error "The 'og:image' property should be explicitly provided, even if a value can be inferred from other tags."
  I am using wordpress theme with default Open Graph </p>
  
  <pre><code>        &lt;!--Facebook Open Graph--&gt;
  &lt;?php if ( defined('WPSEO_VERSION') ) {}else{?&gt;
  &lt;!--FB page title--&gt;
  &lt;meta property="og:title" content="&lt;?php if (! function_exists('bp_is_active') ) {if (is_single() || is_page()) {echo esc_attr(get_the_title());} else {bloginfo('name');}}else {if (is_single() || is_page() &amp;&amp; !is_buddypress()) {echo esc_attr(get_the_title());} elseif(is_buddypress()){wp_title();} else {bloginfo('name');}} ?&gt;" /&gt;
  &lt;!--FB description--&gt;
  &lt;meta property="og:description" content="&lt;?php if (is_single()) {echo substr(strip_tags($post-&gt;post_content), 0, 200); echo '...';} else {bloginfo('description');} ?&gt;"/&gt;
  &lt;!--FB url--&gt;
  &lt;meta property="og:url" content="&lt;?php if ( is_home() || is_front_page() ){echo esc_url(home_url('/'));} else{the_permalink();} ?&gt;"/&gt;
  &lt;!--FB image--&gt;
  &lt;meta property="og:image" content="&lt;?php if (is_single()) {$fbthumb = wp_get_attachment_image_src(get_post_thumbnail_id(), 'slider-three'); echo esc_url($fbthumb[0]);} else {echo esc_url(get_option('exm1_facebook_default'));}?&gt;" /&gt;
  &lt;!--FB type--&gt;
  &lt;meta property="og:type" content="&lt;?php if (is_single()) { echo "article"; } else { echo "website";} ?&gt;"/&gt;
  &lt;!--FB site name--&gt;
  &lt;meta property="og:site_name" content="&lt;?php bloginfo('name'); ?&gt;"/&gt;
  &lt;?php } ?&gt;
  &lt;?php wp_head(); ?&gt;
  &lt;div id="fb-root"&gt;&lt;/div&gt;
  &lt;script&gt;(function(d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); js.id = id;
    js.src = 'https://connect.facebook.net/en_GB/sdk.js#xfbml=1&amp;version=v2.10&amp;appId=546337812226292';
    fjs.parentNode.insertBefore(js, fjs);
  }(document, 'script', 'facebook-jssdk'));&lt;/script&gt;
  </code></pre>
  
  <p>When I debug on Facebook, Fabook debugger show me og.image url and I try to view image but it's look not found page. I am also using EWWW Image Optimizer plugin for image optimization. I don't know What i do now and why wordpress not showing image on default url. Please help me. Website: <a href="http://urdukhabrain.pk" rel="nofollow noreferrer">http://urdukhabrain.pk</a></p>