The Save the Process Image option saves an image of the current process to the Photo Library on your device. This is a very convenient way of using the output of the process for other areas. One of the things that you may do with this is create the process and then save it to your photo library. You may have a Pages document that you use to edit your document and then insert the image of the process that was saved.
and then you will see the image in your Photo Library where you can share, text, tweet, print, etc.