Mozilla & Explorer HTML differences?

For some reason, Mozilla doesn’t react the same way as Explorer when it comes to using percentages in the tables. I keep getting a small area of space in the bottom of the page, this doesn’t come up with Explorer, I was wondering if someone can tell me how ot get rid of the small space in the bottom? Below is my core HTML coding:

<body bgcolor="#FFFFFF" leftmargin=“0” topmargin=“0”>
<center>
<table width=“295” height=“100%” border=“0” align=“center” cellpadding=“0” cellspacing=“0”>
<tr>
<td width=“295” height=“100%” align=“center” valign=“top”>
<table width=“295” height=“100%” border=“0” align=“center” cellpadding=“0” cellspacing=“0”>
<tr>
<td width=“295” height=“30%” align=“center”></td>
</tr>
<tr>
<td width=“295” height=“70%” align=“center” valign=“bottom”>
<img src=“images/splash.jpg” width=“295” height=“450” border=“0”>
</td>
</tr>
</table>
</td>
</tr>
</table>
</center>
</body>