Optimal header image sizes and settings

If you want to adjust your image more specifically, try unchecking parallax and play around withe the background settings so that you can pick a focal point, like center center. 

As an example of my page:

http://demo.themovation.com/bellevue/hotel/explore/

Here is the background settings to make the image stay crisp while centering it properly:

Actual image link (1400 x 600)

I'm viewing your site on a 1920 x 1200 monitor.