View source  
  <?php
namespace Drupal\media\Plugin\media\Source;
use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Entity\EntityFieldManagerInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Field\FieldTypePluginManagerInterface;
use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Image\ImageFactory;
use Drupal\media\MediaInterface;
use Drupal\media\MediaTypeInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
class Image extends File {
  
  const METADATA_ATTRIBUTE_WIDTH = 'width';
  
  const METADATA_ATTRIBUTE_HEIGHT = 'height';
  
  protected $imageFactory;
  
  protected $fileSystem;
  
  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, FieldTypePluginManagerInterface $field_type_manager, ConfigFactoryInterface $config_factory, ImageFactory $image_factory, FileSystemInterface $file_system) {
    parent::__construct($configuration, $plugin_id, $plugin_definition, $entity_type_manager, $entity_field_manager, $field_type_manager, $config_factory);
    $this->imageFactory = $image_factory;
    $this->fileSystem = $file_system;
  }
  
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container
      ->get('entity_type.manager'), $container
      ->get('entity_field.manager'), $container
      ->get('plugin.manager.field.field_type'), $container
      ->get('config.factory'), $container
      ->get('image.factory'), $container
      ->get('file_system'));
  }
  
  public function getMetadataAttributes() {
    $attributes = parent::getMetadataAttributes();
    $attributes += [
      static::METADATA_ATTRIBUTE_WIDTH => $this
        ->t('Width'),
      static::METADATA_ATTRIBUTE_HEIGHT => $this
        ->t('Height'),
    ];
    return $attributes;
  }
  
  public function getMetadata(MediaInterface $media, $name) {
    
    
    $file = $media
      ->get($this->configuration['source_field'])->entity;
    
    if (!$file) {
      return parent::getMetadata($media, $name);
    }
    $uri = $file
      ->getFileUri();
    switch ($name) {
      case static::METADATA_ATTRIBUTE_WIDTH:
        $image = $this->imageFactory
          ->get($uri);
        return $image
          ->getWidth() ?: NULL;
      case static::METADATA_ATTRIBUTE_HEIGHT:
        $image = $this->imageFactory
          ->get($uri);
        return $image
          ->getHeight() ?: NULL;
      case 'thumbnail_uri':
        return $uri;
      case 'thumbnail_alt_value':
        return $media
          ->get($this->configuration['source_field'])->alt ?: parent::getMetadata($media, $name);
    }
    return parent::getMetadata($media, $name);
  }
  
  public function createSourceField(MediaTypeInterface $type) {
    
    $field = parent::createSourceField($type);
    
    $settings = $this->fieldTypeManager
      ->getDefaultFieldSettings($field
      ->getType());
    return $field
      ->set('settings', $settings);
  }
  
  public function prepareViewDisplay(MediaTypeInterface $type, EntityViewDisplayInterface $display) {
    parent::prepareViewDisplay($type, $display);
    
    $field_name = $this
      ->getSourceFieldDefinition($type)
      ->getName();
    $component = $display
      ->getComponent($field_name);
    $component['settings']['image_link'] = '';
    $component['settings']['image_style'] = '';
    if ($this->entityTypeManager
      ->getStorage('image_style')
      ->load('large')) {
      $component['settings']['image_style'] = 'large';
    }
    $display
      ->setComponent($field_name, $component);
  }
}