Xpressengine\Media\MediaManager::createThumbnails PHP Method

    public function createThumbnails(Media $media, $type = null)
    {
        $type = strtolower($type ?: $this->config['type']);
        $handler = $this->getHandlerByMedia($media);
        if (!($content = $handler->getPicture($media))) {
            return [];
        }
        $thumbnails = [];
        foreach ($this->config['dimensions'] as $code => $dimension) {
            $command = $this->factory->make($type);
            $command->setDimension(new Dimension($dimension['width'], $dimension['height']));
            $thumbnails[] = $this->getHandler(Media::TYPE_IMAGE)->createThumbnails($content, $command, $code, $this->config['disk'], $this->config['path'], $media->getOriginKey());
        }
        return new Collection($thumbnails);
    }

 /**
  * file upload
  *
  * @param Request       $request      request
  * @param EditorHandler $handler      editor handler
  * @param Storage       $storage      storage
  * @param MediaManager  $mediaManager media manager
  * @param string        $instanceId   instance id
  * @return RendererInterface
  */
 public function fileUpload(Request $request, EditorHandler $handler, Storage $storage, MediaManager $mediaManager, $instanceId)
 {
     $uploadedFile = null;
     if ($request->file('file') !== null) {
         $uploadedFile = $request->file('file');
     } elseif ($request->file('image') !== null) {
         $uploadedFile = $request->file('image');
     }
     if ($uploadedFile === null) {
         throw new InvalidArgumentException();
     }
     $config = $handler->get($instanceId)->getConfig();
     if (!$config->get('uploadActive') || Gate::denies('upload', new Instance($handler->getPermKey($instanceId)))) {
         throw new AccessDeniedHttpException();
     }
     if ($config->get('fileMaxSize') * 1024 * 1024 < $uploadedFile->getSize()) {
         throw new HttpException(Response::HTTP_REQUEST_ENTITY_TOO_LARGE, xe_trans('xe::msgMaxFileSize', ['fileMaxSize' => $config->get('fileMaxSize'), 'uploadFileName' => $uploadedFile->getClientOriginalName()]));
     }
     $extensions = array_map(function ($v) {
         return trim($v);
     }, explode(',', $config->get('extensions', '')));
     if (array_search('*', $extensions) === false && !in_array(strtolower($uploadedFile->getClientOriginalExtension()), $extensions)) {
         throw new HttpException(Response::HTTP_NOT_ACCEPTABLE, xe_trans('xe::msgAvailableUploadingFiles', ['extensions' => $config->get('extensions'), 'uploadFileName' => $uploadedFile->getClientOriginalName()]));
     }
     $file = $storage->upload($uploadedFile, EditorHandler::FILE_UPLOAD_PATH);
     $media = null;
     $thumbnails = null;
     if ($mediaManager->is($file) === true) {
         $media = $mediaManager->make($file);
         $thumbnails = $mediaManager->createThumbnails($media, EditorHandler::THUMBNAIL_TYPE);
         $media = $media->toArray();
         if (!empty($thumbnails)) {
             $info['thumbnails'] = $thumbnails;
         }
     }
     return XePresenter::makeApi(['file' => $file->toArray(), 'media' => $media, 'thumbnails' => $thumbnails]);
 }