When image synthesis using form data, for which a pass code has been set, or merge data, for which a password has been set, is completed, the synthesized data is encoded and held. Thereafter, a client terminal is notified by e-mail that image synthesis has been completed. Thereafter, when a request for output is inputted, collation of passwords is carried out. If the passwords match, decoding and printing-out of encoded synthesized data, or transmission of the encoded synthesized data is carried out.