Hello,
You need to set width value without px or %. For example:
<td width="33%" ><img width="50" src="image.png"></td>
Since HTML5, width and height values in this tag must be in pixels and without adding 'px' (http://www.w3schools.com/tags/att_img_width.asp).
We also recommend you to check that Tidy is installed and running on your server.
Regards.