Ok I ran some tests. Sometimes it is removed when switching from HTML to Normal mode, but not removed when you click show HTML if you don't go to Normal or Preview mode first. Also, sometimes a whole image is removed when switching from HTML to Normal mode, in your example
<td>
<p><img onmouseover="alert('HI')" height="53" src="http://cutesoft.net/Uploads/j0262681.jpg" width="80" alt="" /></p>
</td>
Is changed to
I would expect it to not remove the whole image?
Jason