[Drupal 8] Create file/ media_entity programmatically

file_media_entity.php

<?php 
$filesystem = \Drupal::service('file_system');
// Create file entity.
$image = File::create();
$image->setFileUri($destination);
$image->setOwnerId(\Drupal::currentUser()->id());
$image->setMimeType('image/' . pathinfo($destination, PATHINFO_EXTENSION));
$image->setFileName($filesystem->basename($destination));
$image->setPermanent();
$image->save();
// Create media entity with saved file.
$image_media = Media::create([
  'bundle' => 'image',
  'uid' => \Drupal::currentUser()->id(),
  'langcode' => \Drupal::languageManager()->getDefaultLanguage()->getId(),
  'status' => Media::PUBLISHED,
  'field_image' => [
    'target_id' => $image->id(),
    'alt' => t('Placeholder image'),
    'title' => t('Placeholder image'),
  ],
 ]);
$image_media->save();

ImageRenderExampleBlock.php

<?php

/**
 * @file
 * Contains Drupal\mymodule\Plugin\Block\ImageRenderExampleBlock.
 */

namespace Drupal\mymodule\Plugin\Block;

use Drupal\Core\Block\BlockBase;
use Drupal\file\Entity\File;

/**
 * Provides a 'ImageRenderExampleBlock' block.
 *
 * @Block(
 *  id = "mymodule_imagerenderexampleblock",
 *  admin_label = @Translation("MyModule Image Render Example"),
 * )
 */
class ImageRenderExampleBlock extends BlockBase {

  /**
   * {@inheritdoc}
   */
  public function build() {
    // Load file with file id 1.
    $file = File::load(1);
    if ($file) {
      $variables = array(
        'style_name' => 'thumbnail',
        'uri' => $file->getFileUri(),
      );

      // The image.factory service will check if our image is valid.
      $image = \Drupal::service('image.factory')->get($file->getFileUri());
      if ($image->isValid()) {
        $variables['width'] = $image->getWidth();
        $variables['height'] = $image->getHeight();
      }
      else {
        $variables['width'] = $variables['height'] = NULL;
      }

      $logo_build = [
        '#theme' => 'image_style',
        '#width' => $variables['width'],
        '#height' => $variables['height'],
        '#style_name' => $variables['style_name'],
        '#uri' => $variables['uri'],
      ];

      // Add the file entity to the cache dependencies.
      // This will clear our cache when this entity updates.
      $renderer = \Drupal::service('renderer');
      $renderer->addCacheableDependency($logo_build, $file);

      // Return the render array as block content.
      return [
        'logo' => $logo_build,
      ];
    } else {
      // Image not found, return empty block.
      return [];
    }
  }
}

ImageRenderExampleBlockResponsive.php

<?php

/**
 * @file
 * Contains Drupal\mymodule\Plugin\Block\ImageRenderExampleBlockResponsive.
 */

namespace Drupal\mymodule\Plugin\Block;

use Drupal\Core\Block\BlockBase;
use Drupal\file\Entity\File;

/**
 * Provides a 'ImageRenderExampleBlockResponsive' block.
 *
 * @Block(
 *  id = "mymodule_imagerenderexampleblockresponsive",
 *  admin_label = @Translation("MyModule Image Render Example Responsive"),
 * )
 */
class ImageRenderExampleBlockResponsive extends BlockBase {

  /**
   * {@inheritdoc}
   */
  public function build() {
    // Load file with file id 1.
    $file = File::load(1);
    if ($file) {
      $variables = array(
        'responsive_image_style_id' => 'responsive_thumbnail',
        'uri' => $file->getFileUri(),
      );

      // The image.factory service will check if our image is valid.
      $image = \Drupal::service('image.factory')->get($file->getFileUri());
      if ($image->isValid()) {
        $variables['width'] = $image->getWidth();
        $variables['height'] = $image->getHeight();
      }
      else {
        $variables['width'] = $variables['height'] = NULL;
      }

      $logo_build = [
        '#theme' => 'responsive_image',
        '#width' => $variables['width'],
        '#height' => $variables['height'],
        '#responsive_image_style_id' => $variables['responsive_image_style_id'],
        '#uri' => $variables['uri'],
      ];

      // Add the file entity to the cache dependencies.
      // This will clear our cache when this entity updates.
      $renderer = \Drupal::service('renderer');
      $renderer->addCacheableDependency($logo_build, $file);

      // Return the render array as block content.
      return [
        'logo' => $logo_build,
      ];
    } else {
      // Image not found, return empty block.
      return [];
    }
  }
}