Do people still use the old HTML Image Maps? The ones with:
An alternative solution to using CSS or image maps would be to make use of SVG graphics embedded into the HTML dom.
One tutorial on how to achieve mouseover effects using this technique is described in this tutorial: http://www.petercollingridge.co.uk/data-visualisation/mouseover-effects-svgs
The key takeaway being that SVG elements also trigger traditional dom events including onmouseover and onmouseout.