core-bundle/src/Resources/contao/library/Contao/Automator.php
public function purgeImageCache()
	{
		$container = System::getContainer();
		$strTargetPath = StringUtil::stripRootDir($container->getParameter('contao.image.target_dir'));
		$strRootDir = $container->getParameter('kernel.project_dir');

		// Walk through the subfolders
		foreach (scan($strRootDir . '/' . $strTargetPath) as $dir)
		{
			if (strncmp($dir, '.', 1) !== 0)
			{
				$objFolder = new Folder($strTargetPath . '/' . $dir);
				$objFolder->purge();
			}
		}

		// Also empty the page cache so there are no links to deleted images
		$this->purgePageCache();

		// Add a log entry
		$this->log('Purged the image cache', __METHOD__, TL_CRON);
	}
public function purgeImageCache()
	{
		$container = System::getContainer();
		$strTargetPath = StringUtil::stripRootDir($container->getParameter('contao.image.target_dir'));
		$strRootDir = $container->getParameter('kernel.project_dir');

		// Walk through the subfolders
		foreach (scan($strRootDir . '/' . $strTargetPath) as $dir)
		{
			if (strncmp($dir, '.', 1) !== 0)
			{
				$objFolder = new Folder($strTargetPath . '/' . $dir);
				$objFolder->purge();
			}
		}

		// Also empty the page cache so there are no links to deleted images
		$this->purgePageCache();

		// Add a log entry
		$this->log('Purged the image cache', __METHOD__, TL_CRON);
	}
Purge the image cache