Mobile devices cannot render image maps. Image maps require exact pixels widths which cause havoc on mobile phones.
May I suggest that an image map when rendered is also tied to a fallback set of links to the pages it links to and is only revealed at a certain threshold (768px correspond with most tablet sizes)?
Suggested code below:
imagemap { display: none; } @media all and (min-width: 768px) { imagemap { display: block; } imagemap .fallback { display: none; } }