Zerif Lite Header Background resized (small)

Dear all,

I checked my website today: http://www.globaltradegroup.eu, and suddenly without any changes I made the header (background) was resized to a really small balk.

I have tried, to check in style.css couldn’t find anything that could help me out.

Already tried changing the Image, result is it stays the same.

When you use an apple and scroll up really quick, you can see the welcome message and the full image but it automatticly drops back when you stop scrolling up.

Please help me out!

Regards,