code: protected function persistConfiguration(array $config) : bool
      {
          $configurationFileName = PATH_site . 'typo3conf/image_autoresize.config.php';
  
          $exportConfig = var_export($config, true);
          $exportConfig = str_replace('array (', '[', $exportConfig);
          if (substr($exportConfig, -1) === ')') {
              $exportConfig = substr($exportConfig, 0, strlen($exportConfig) - 1) . ']';
          }
          $exportConfig = preg_replace('/=>\\s*[[]/s', '=> [', $exportConfig);
          $lines = explode(LF, $exportConfig);
          foreach ($lines as $i => $line) {
              if (preg_match('/^(\\s+)(.+)$/', $line, $matches)) {
                  if ($matches[2] === '),') {
                      // Convert ending of former array declaration to new syntax
                      $matches[2] = '],';
                  }
                  $lines[$i] = str_repeat(' ', 2 * strlen($matches[1])) . $matches[2];
              }
          }
          $exportConfig = implode(LF, $lines);
  
          $content = '<?' . 'php' . LF . 'return ' . $exportConfig . ';' . LF;
          $success = GeneralUtility::writeFile($configurationFileName, $content);
          return true;
      }
docs: Writes configuration to typo3conf/image_autoresize.config.php.
  
  @param array $config
  @return bool