add class nav a, nav a:visited to media querry 850px so the padding around the image will be less and the image will get bigger in small screen.
add class col-1of3-insight-withmargin img and col-10f3-insight img to control the image size when the screen get smaller ( it is in media query 850px).
add margin-left 0 to col-1of3-insight-withmargin class.
add overflow: hidden to class col-1of3-insight-withmargin.
add overflow hidden to class col-1of3-insight.