How To hide a file behind an image

To hide a file behind a image file which means that if any one opens that image he will see the image only but if you open in a special way then you can open the hidden file behind the image.
So to hide the file behind a image open CMD.exe

1) Select an image to be used for hiding file behind the image.
2) Now select a file to hide behind the image and make it in .RAR format. With the help of the WinRAR.
3) And most important is that paste both the files on desktop and run the following command on the command prompt.
4) And then type the following command.
cd desktop
Copy /b imagename.jpg + filename.rar finalnameofimage.jpg