Hide the file behind an Image (hacking)

The hackers intention is to catch the passwords and to play with the clients, that i have done
One trick among them is hiding the content(software/virus/sfx) behind the image
open the command.com and type the following

copy \b sourceimage.jpg + sourcefile.zip destination.jpg

copy: a cmd line command
\b: binary conversion.
source image: u r source image. (should be in .jpg)
dest image : u r destinatin image. (should be in .jpg)
source zip file: compress any-thing in a zip file.