X-Cart forums - problems with css

I'm trying to do a new skin for my site which will be upgraded to 4.0.18 and I just can't get the css to work.

Every css app I use seems to think it's all OK, but it's just not displaying, so maybe I'm being really thick?

This is part of the source html:

Code:

<TR><TD height="100%">[img]/xcart/skin1/images/spacer.gif[/img]</TD></TR>



        <tr>

                <td>

                        [img]/xcart/skin1/images/wtc_10.jpg[/img]</td>

                <td>

                        [img]/xcart/skin1/images/wtc_11.jpg[/img]</td>

                <td><div class="cell12">Copyright &copy; 2004-2006 Willow Tree Crafts</div></td>



                <td>



                        [img]/xcart/skin1/images/wtc_13.jpg[/img]</td>

        </tr>

and this is the css style that I think should apply:

Code:

.cell12 {

        background: #ffffff url(images/wtc_12.jpg) repeat-x  top;

}

The only thing I can think of is that the problem is in the url, but The images are in the skin1/images folder which is where I think I am referencing?

I have just changed the css file to background: #000000; and the right section has gone black so I think it must be in the file reference.

Can anyone help me?

tia

Amy
(for a 4.0.18 site)