Yes, you can hide any file within a JPG picture easily. All you need is a picture which should be in JPG format and a file of any extension/type. The procedure is simple. Simply add all files you want to hide to a RAR (WinRAR) file and use the following command in DOS to embed this RAR file in an image.
copy /b Oldimage.jpg + data.rar Newimage.jpg
Where:

Data.rar = RAR file which contains the files you want to hide.
Oldimage.jpg = File in which data.rar will be hidden.
Newimage.jpg = New image file which contains data.rar hidden in it.

To retrieve hidden files back from Newimage.jpg, just change the extension of Newimage.jpg from JPG to RAR and then extract hidden files from it via WinRar.

Here is a video tutorial in which i am hiding Tutorial.txt in Techtoggle.jpg