Here's the trick:
1) Take two files -
one which you want to hide and another will be the jpg image(of any size and dimension)to hide that file
If you want to hide multiple files in one jpeg image, just zip them into one file
2) To make the process easy, Copy the above two files to the C:
3) Now open the command prompt (Go to start, Click "RUN" and type "cmd").
4) get to the root by typing cd\ or you can give the path name where the files are located
5) Now type the following command:
copy /b imagename.jpg + filetohide.ext new_image.jpg
6) Now a new file new_image.jpg will be created
7) Double click on the file and it will open the image which you used to hide the secret file
8) To access the hidden file simply change the extension from jpg to orignal extension of the hidden file,
Example: I took an image filename "myphoto.jpg"
I wanted to hide some important word documents so I zipped all the word files and created a zip file "word.zip"
Then copied both "myphoto.jpg" and "word.zip" to c:
Opened the command prompt
Typed the command: copy /b myphoto.jpg + word.zip new_image.jpg
Now I have a new file "new_image.jpg" in C:
When I double click on the new file it shows me the image of "myphoto.jpg"
If I change the extension of new_image.jpg to new_image.zip I can extract the contents of the word.zip file