Header Image and Responsive Issues

Hey all,

We are about to launch our blog with Ashe theme and noticed some issues:

1. The header image looks perfect when viewed on Mac laptop. However, by chance, I viewed the site on my desktop computer at work today, which is a wide screen, and the header image gets blown up so large that the top and bottom parts of the image get cut off. It is not fixed by scrolling up or down. When the size of the window is decreased, the image comes back into focus and is no longer cut off.

Is there a way to fix this/prevent the image from getting sized out of proportion when expanding to fit a larger screen?

2. When viewing on a cell phone, the opposite problem happens. The header image and entire blog is non-responsive, and doesn’t get changed to fit a small screen of a mobile phone. Is this the case with the theme in general? How can I make it look nice on a cell phone?

Thanks so much!