I have got a background image that is not doing what it *should* on breakpoints sub 480. It should be fixed and is set to cover the visible screen but when you get to 480 and below, its neither of those things.
It works fine and as expected if you view it on a desktop browser at that resolution but if you look at it on a mobile device thats when it starts fritzing

If you look at this page https://goo.gl/y1r4db on both a desktop (at 480 resolution and below) and also a mobile device you'll see the difference in what is happening. Heres a link also to the rsd file: https://goo.gl/T13ZnY
Thanks in advance
Jamie