The following conditions are wrong
https://github.com/phpbb/phpbb/blob/ed9cbc89c19bc6321bfdd540f241683b71ea9a6e/phpBB/phpbb/avatar/driver/gravatar.php#L117
https://github.com/phpbb/phpbb/blob/ed9cbc89c19bc6321bfdd540f241683b71ea9a6e/phpBB/phpbb/captcha/gd.php#L93