The same way as you use a background image with any other element. CSS basically doesn't care about if it's a P, a DIV, a TD or any other element.
http://htmlhelp.com/reference/css/color-ba...background.htmlIf you want the background for just one cell of many, you have to use a selctor that singles that cell out. If nothing else fits, class the TD.
CSS;
CODE
.rumpelstiltskin { background: #abc012 url(background.jpg) }
HTML
<td class="rumpelstiltskin">...</td>