Simply put the file you want and the image in one folder and make sure that the image is x.jpg and x is your image name .then hold the right shift and press right click and select (open command prompt here) after open the command prompt type copy /b x.jpg+x.rar x.jpg thats it and to open the hidden file eithe rename it to rar or zip or open it with winrar or 7zip or any compressing app
