Don't do it the intuitive way...
<table>
<tr style="background: url(/images/tr-background.gif) no-repeat 0 0;">
<td>Row 1</td>
<td>Row 2</td>
<td>Row 3</td>
</tr>
</table>
<tr style="background: url(/images/tr-background.gif) no-repeat 0 0;">
<td>Row 1</td>
<td>Row 2</td>
<td>Row 3</td>
</tr>
</table>
...because it doesn't work in IE6 or Safari, even if you set the <td> background element to 'transparent' or 'none'.
But you can still make it happen with just the one image:
<table>
<tr>
<td style="background: url(/images/tr-background.gif) no-repeat 0 0;">Row 1</td>
<td style="background: url(/images/tr-background.gif) no-repeat 50% 0;">Row 2</td>
<td style="background: url(/images/tr-background.gif) no-repeat 100% 0;">Row 3</td>
</tr>
</table>
<tr>
<td style="background: url(/images/tr-background.gif) no-repeat 0 0;">Row 1</td>
<td style="background: url(/images/tr-background.gif) no-repeat 50% 0;">Row 2</td>
<td style="background: url(/images/tr-background.gif) no-repeat 100% 0;">Row 3</td>
</tr>
</table>
You're just altering the background-position of the image, so that what should be on the left goes on the left (at 0), the middle part goes to the middle (50% horizontally), and the last part goes at the end (100%). Remember that values in the background-position element are ordered horizontal, then vertical, unlike the margin and padding elements.
And, of course, you'll want to separate presentation from content by putting the CSS elsewhere and classing the td's.
