code: private function createConfig($size): array
      {
          if (!\is_array($size)) {
              $size = [0, 0, $size];
          }
  
          $config = new PictureConfiguration();
          $attributes = [];
  
          if (!isset($size[2]) || !is_numeric($size[2])) {
              $resizeConfig = new ResizeConfiguration();
  
              if (!empty($size[0])) {
                  $resizeConfig->setWidth((int) $size[0]);
              }
  
              if (!empty($size[1])) {
                  $resizeConfig->setHeight((int) $size[1]);
              }
  
              if (!empty($size[2])) {
                  $resizeConfig->setMode($size[2]);
              }
  
              $configItem = new PictureConfigurationItem();
              $configItem->setResizeConfig($resizeConfig);
  
              if ($this->defaultDensities) {
                  $configItem->setDensities($this->defaultDensities);
              }
  
              $config->setSize($configItem);
  
              return [$config, $attributes];
          }
  
          /** @var ImageSizeModel $imageSizeModel */
          $imageSizeModel = $this->framework->getAdapter(ImageSizeModel::class);
          $imageSizes = $imageSizeModel->findByPk($size[2]);
  
          $config->setSize($this->createConfigItem($imageSizes));
  
          if ($imageSizes && $imageSizes->cssClass) {
              $attributes['class'] = $imageSizes->cssClass;
          }
  
          /** @var ImageSizeItemModel $imageSizeItemModel */
          $imageSizeItemModel = $this->framework->getAdapter(ImageSizeItemModel::class);
          $imageSizeItems = $imageSizeItemModel->findVisibleByPid($size[2], ['order' => 'sorting ASC']);
  
          if (null !== $imageSizeItems) {
              $configItems = [];
  
              foreach ($imageSizeItems as $imageSizeItem) {
                  $configItems[] = $this->createConfigItem($imageSizeItem);
              }
  
              $config->setSizeItems($configItems);
          }
  
          return [$config, $attributes];
      }
docs: Creates a picture configuration.
  
  @param int|array|null $size
  
  @return (PictureConfiguration|array<string,string>)[]