background image loads slowly

Hi,
Ive done some research and even installed ewww image optimizer plug in and can’t get my image to fit all monitor screens perfectly. And the loading time of my background image is rather slow.

I’d like to know if there are any css codes I can use or plug ins that may help resolve this issue. Or how I can go into my stylesheet css to fix this.

I am using wordpress.org landscape theme

here is a link to my website
http://www.jordanwhitlockmusic.com

thank you so much an advance!!