Full background picture

Hi, I am terrible at this and I wanted some help.
When you select a background picture it only shows up like an inch on all sides, how do you make it the entire background? (full screen BG image did not help…)
Strange thing is that I managed to get a full background for the home page, but not the other pages (I have no idea how I did that… only that I have changed the appearance of the original home page to the one I have now – so maybe there’s a connection).
I would like to also change the background of the widgets on the right hand side of the page. How do I do that, but still keep the black frame?
I have responsive theme.
Site: http://www.biometricanalysis.com/the-hand-brain-connection/

Also, am trying to learn how to put a Facebook “Like” icon on the main page. Any advice would be much appreciated.
Thank you!!