The notification is the specification
UPSC publishes photograph and signature requirements in each examination's notification, and they have been revised — including the introduction of a requirement that the photograph carry the date on which it was taken. A figure from an earlier year or a third-party page can be wrong in a way that is only discovered at rejection.
Recent notifications have also required the photograph to be taken within a specified window before the application. That is not something a resizer can fix, and it is worth reading before spending time on the crop.