Graphics are often a problem in responsive layouts designed to adapt automatically to different device sizes – from desktop monitors to hand-held smartphones. Traditionally, graphics have fixed dimensions that break responsive layouts on screens that are smaller than the graphic.
To solve this problem you need to set the width of your graphics in percent relative to the page dimensions. Then the graphic can never be wider than the page. Length is not a problem, because pages can always scroll vertically. However, you never want the page to have to scroll horizontally on mobile devices with fluid layouts.