How do I add a photo to an existing PDF document?

I am trying to add a photo; jpeg, I believe, to an existing PDF document that contains text bubbles and boxes. Can anyone tell me how to accomplish this?  I don't appear to have a tools setting that I can tell, my tool bar only allows me to send a PDF, convert to a PDF, add text to it or go to home page to select documents.  I am at a loss.