Placing image at bottom of page?

I just started building my website today, and I don't have any previous experience with web design. My problem is that I am trying to place an image at the bottom of my page that repeats across the screen. I want it to appear in front of my background image. I'm not sure whether or not this is even possible to achieve.

Here is my website for reference http://www.pizzadog.net/ and here is the url to the image I am trying to display across the bottom http://i.imgur.com/r0IS5.png. I have looked through similar threads and the solutions do not seem to work. I appreciate any help.