How to use wp_get_attachment_metadata for thumbnails

I would like to add the right rich text snippets so that the Goole Structured Data validator will pass all the code I have. The only things missing are the sizes of the thumbnails.

This specific examples is for the thumbnails in the loop of the WordPress homepage.

I have this code:

<div itemprop="image" itemscope itemtype="https://schema.org/ImageObject">
                        <meta itemprop="url" content="<?php echo wp_get_attachment_thumb_url( get_post_thumbnail_id( $post->ID ) ); ?>">
                    <?php if ( has_post_thumbnail() ) {
the_post_thumbnail( 'full', array('class'=>'post_thumbnail_common', 'alt' => get_the_title() , 'title' => get_the_title() ));
echo contentnoimg(41);} else { echo content(41); } ?>
                        </div>

Here I want to add the following:

<meta itemprop="width" content="800">
<meta itemprop="height" content="800">

So that the final code will look something like this:

<div itemprop="image" itemscope itemtype="https://schema.org/ImageObject">
                        <meta itemprop="url" content="<?php echo wp_get_attachment_thumb_url( get_post_thumbnail_id( $post->ID ) ); ?>">
<meta itemprop="width" content="<?php XXX ?>">
<meta itemprop="height" content="<?php XXX ?>">
                    <?php if ( has_post_thumbnail() ) {
the_post_thumbnail( 'full', array('class'=>'post_thumbnail_common', 'alt' => get_the_title() , 'title' => get_the_title() ));
echo contentnoimg(41);} else { echo content(41); } ?>
                        </div>

How should I put instead of so that the image height and width will be well collected?

Here are the content and contentnoimg functions – they format the excerpt shown after the thumbnail and crop it after X characters:

function content( $limit ) {
    global $post;

    if( has_excerpt() ){
        $content = the_excerpt();
    } else {
      $content = explode( ' ', get_the_content(), $limit );
      if ( count($content) >= $limit ) {
        array_pop( $content );
        $content = implode( " ", $content );
        $content = wp_strip_all_tags( $content, true );
// $content .= '...<br><a href="'. get_permalink($post->ID) . '" class="awesomebtn">'.__('Read full post','language') .'</a>';
      } else {
        $content = implode( " ", $content );
      }

      $content = preg_replace( '/\[.+\]/','', $content );
      $content = apply_filters( 'the_content', $content ); 
      $content = str_replace( ']]>', ']]&gt;', $content );
    }

    return $content;
}



function contentnoimg($limit) {
     global $post;
         if( has_excerpt() ){
        $content = the_excerpt();
    } else {     
      $content = explode(' ', get_the_content(), $limit);
      if (count($content)>=$limit) {
        array_pop($content);
        $content = implode(" ",$content);
$content = wp_strip_all_tags($content, true);
// $content .= '...<br><a href="'. get_permalink($post->ID) . '" class="awesomebtn">'.__('Read full post','language') .'</a>';
      } else {
        $content = implode(" ",$content);
      }   
      $content = preg_replace('/(<img.+?>)/','', $content);
      $content = apply_filters('the_content', $content); 
      $content = str_replace(']]>', ']]&gt;', $content);
    }
      return $content;
    }

Thanks

The structure would be something like this.

• Check if you have a thumbnail
• Get the meta
• Add the meta data for w/h/file

• Then render the image

  if ( has_post_thumbnail() ) : // check if the post has a Post Thumbnail assigned to it.
  
  $upload_dir = wp_upload_dir();
  
  $size="full";
  
  $post_thumbnail_id = get_post_thumbnail_id( $post_id );
  $post_thumbnail_meta = wp_get_attachment_metadata ( $post_thumbnail_id );
  $main_file = $post_thumbnail_meta [ 'file' ];
  $dirname = dirname ( $main_file );
  $base_url = trailingslashit ( $upload_dir['baseurl'] ) . $dirname . "https://wordpress.stackexchange.com/";
  
  // fallback to known file if the size doesn't exist
  if ( ! isset($post_thumbnail_meta [ 'sizes' ][ $size ] ) )
  {
      $size="full"; // use this size when we're missing data
  }
  
  // full is at the root, alternate sizes exist in the sizes prop
  $imgInfo = $size === 'full' ? $post_thumbnail_meta : $post_thumbnail_meta [ 'sizes' ][ $size ];
  $filename = basename ( $imgInfo[ 'file' ] );
  $width = $imgInfo[ 'width' ];
  $height = $imgInfo[ 'height' ];
  $file = $base_url . $filename;
  
  ?>
  <div itemprop="image" itemscope itemtype="https://schema.org/ImageObject">
      <meta itemprop="url" content="<?php echo $file; ?>">
      <meta itemprop="width" content="<?php echo $width; ?>">
      <meta itemprop="height" content="<?php echo $height; ?>">
  
      <?php
          the_post_thumbnail( 'full', array('class'=>'post_thumbnail_common', 'alt' => get_the_title() , 'title' => get_the_title() ) );
  
          echo contentnoimg(41);
      ?>
  </div>
  <?php
  
  else:  // end has_post_thumbnail else
  
      // no thumbnail
      echo content(41); 
  
  endif; // end has_post_thumbnail block