//Correct, working code

<ul class="hoverbox">
<li><img  src="assets/specimages/_resampled/ResizedImage10067-3.jpg" alt="description" onmouseover=show_200("assets/specimages/3.jpg","image_3",418,280) onmouseout=hide_div() onerror=gag(this,100) /></li>
</ul>


//Code after SS/TinyMCE is finished with it.

<ul class="hoverbox">
<li><img onmouseover="show_200("assets/specimages/3.jpg","image_3",418,280)" onmouseout="hide_div()" src="assets/specimages/_resampled/ResizedImage10067-3.jpg" alt="description" /></li>
</ul>