Trouble with background image for container

Hello, I am using the Premium Origami Responsive theme, and this is my first website I’ve ever built (I’m a TOTAL noob, and don’t know how to write code). I had stumbled upon being able to change my background/foreground/container to my home page with an image early on, but now I can only change the background with an image behind the main page (www.ralphmerrick.com).

I have a nice image that I’d like to tile in the foreground (instead of choosing a color that doesn’t look so great) to contrast with my image in the background. Any ideas? If there’s an easy way to do it, I’d love to know. Thanks in advance!