99% of the time it is spaces in the HTML.. especially when it comes to an image in a table cell.
Example from your code:
Code:
<td>
<img src="images/tod_15.jpg" width="120" height="20" alt=""></td>
would be better off as
Code:
<td><img src="images/tod_15.jpg" width="120" height="20" alt=""></td>
Sounds crazy, but it usually fixes those mysterious gaps
