Error on scrolling the page horizontally on website

When the page :http://mesos.apache.org/documentation/latest/architecture/
is scrolled horizontally the naval bar at the top discontinues creating a bad look.
Also, this is occuring only because of the unadjusted size of the picture architecture3.jpg.
This makes two finger-scrolling non-pleasant.
one of the these things can be done:
1. Adjust the image's size.
2. Fix the naval bar on it's position by adding ":fixed" in the CSS class block itself to prevent any issues even in the future.