[Zerif Lite] Background Image

Hi. I have some weird problem with my new WP page. My background image freakin out on my new page. I have the same setting on both pages, I was trying to put background image from first site to other and problem still exist. Page with problem www9.conf.ottopraca.pl/ . Try to change size of window – there is a grey space. How to fix it and set like here nieplaczaprace.com?