Image Map Disables <A> Tag

[ngreenstein]

Hi All,
I've come across a strange problem.
I've got a thumbnail linked to a map. The map specifies three 'columns' through the image, and each column swaps the image on mouseover.
Here's the problem:
No matter what I do, I can't make the image itself be a link. Not even JS works.
It's worth noting that the thumbnail has a title below it in a <span> tag. The <a> tag makes this a link fine. Here's the relevant line of code:

<div class="galBox"><a href=#><img id="gal1Thumb" class="galThumb" src="galThumbPH1.jpg" usemap="#g1Map" alt="Gallery 1 thumbnail" /><span>Gallery 1</span></a></div>
I can provide more code if necessary.
I have tested; and yes, removing the usemap attribute fixes the problem, making the image a link as usual.

This appears to be a problem in Firefox, Safari, and Chrome.
Any ideas?

Thanks in advance!