Aegaeus: hb-box Responsive Images Warping

I’m using HB Themes Aegaeus theme and it’s great except for the fact that one of the shortcode elements (hb-box) is resizing the images.

(Obviously, automatically resizing site elements to fit a mobile device is one of the main reasons to use responsive design, but in this instance, it makes the image subjects look really, REALLY bad.)

http://www.fullyhr.com/about/

How do I maintain the image size-ratio?

This is the shortcode for the images in question:

[hb_image_box image=”http://fullyhr.com/wp-content/uploads/2015/07/headshot_l_amanda.jpg” link=”http://fullyhr.com/portfolio/amanda-mayo-sphr/” title=”Amanda Mayo” subtitle=”SPHR, Founder, Sr HR Consultant”]

I have already tried the following custom css solutions:

.custom-hb-box { width: 100% !important; display:block; height: auto !important; }

.custom-hb-box img { height: auto !important; width: 100% !important; }

However, these make the site time out with a “Website Not Available” error.