Stop my background image from repeating keeping as a set size

I am using a background image sized 1400 x 1050 which looks great until the website is loaded on a screen bigger than 1400 width were the background starts again.
Is there a way of stopping this from happening so perhaps it resizes to fit the screen as if I upload a larger background to accommodate the largest screen size, I wont end up with the same effect on the more standard screen sizes.
I started this yesterday so it the newest version of wordpress and ato. Website is www.stereotypemcr.com
I am using a fixed layout of 920px.
I have searched endlessly on the forum to no luck.
I appreciate any help and direction.

Do a google search using 'CSS background' and read the options

You can set the background image width to 100% and it will expand and contract. I also remember seeing a background image plugin at wordpress.org for this type of thing. You could do a search there as well.