I recently tried to validate my website using your service (it is coded in PHP, but that doesn't appear to be the problem), and it found 3 errors. Upon looking at these, it was an error with using 'background="image"' functions within a <td> tag. So, I asked for a tidy HTML version, and it generated one. I added this in, put the PHP coding in, but the backgrounds in the tables had gone. Does this mean I can't have table backgrounds for valid HTML? If not, why not? And is there an HTML-friendly way to do it if possible?