Here’s some good old instructions that I found to hide a .rar file in a jpeg so that you can open it as either…

1. Get your .rar file and put it in the same directory as a jpeg picture (c:\hidden is a good place to put it)
2. Open up a command prompt by clicking Start/Run and typing “cmd” and click ok.
3. In the DOS window, type “cd c:\hidden” to navigate to the folder
4. Type “copy /b input.jpg + input.rar ouput.jpg
   (where input jpeg is the picture you want to show, input.rar is the file you want to hide and output.jpg will be the name of the new combined file)

That’s it! You can double click the new file and it will show it as a picture, BUT… if you open it with winrar, you will see the files contained. The picture above has a secret file in it, right click and save picture to your computer and then open it with Winrar to see what I put in there!