Dear Basu, NTA will only notify those candidates whose scanned images do not follow within the set guidelines and onlybsuch candidates can make changes during the correction window. Those candidates who haven't received any notification needn't make any changes and their applications are good to go. Even if you want to change your scanned images without any notification, you will not be able to. So, if you haven't received any notification asking you to upload a new scanned image, you are absolutely fine.