John used to work as a Network Administrator for We-are-secure Inc. Now he has resigned from the company for personal reasons. He wants to send out some secret information of the company. To do so, he takes an image file and simply uses a tool image hide and embeds the secret file within an image file of the famous actress, Jennifer Lopez, and sends it to his Yahoo mail id. Since he is using the image file to send the data, the mail server of his company is unable to filter this mail. Which of the following techniques is he performing to accomplish his task?