Neos\Media\Domain\Strategy\ThumbnailGeneratorStrategy::refresh PHP Method

    public function refresh(Thumbnail $thumbnail)
    {
        $generatorClassNames = static::getThumbnailGeneratorClassNames($this->objectManager);
        foreach ($generatorClassNames as $generator) {
            $generator = $this->objectManager->get($generator['className']);
            if (!$generator->canRefresh($thumbnail)) {
                continue;
            }
            $generator->refresh($thumbnail);
            return;
        }
    }

 /**
  * Refreshes this asset after the PersistentResource has been modified
  *
  * @return void
  */
 public function refresh()
 {
     $this->generatorStrategy->refresh($this);
 }