Position background bottom right

First, let me say that this plugin has gotten closer to solving my problems than anything else so far.
However, I have one issue that keeps coming up, especially on mobile viewports. The focus of the image I am using sits in the bottom right of the image. So, I would like my background image to be anchored to the bottom right of the screen, rather than the top left. I tried changing the left: 0; top: 0; in the supersized css file to right: 0; bottom: 0;, but that did not seem to do the trick.

Any help would be much appreciated.
Build site is http://hasnomouth.com if you’d like to check out what I’m talking about.

http://ww.wp.xz.cn/extend/plugins/wp-supersized/