How to use wp_get_attachment_metadata for thumbnails

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