images for background

hi everyone, now I know that to replace a background color of a category strip, table heading, 1st or 2nd table color with AN image by this code:

#[hexcode]"[link to image]"

But then I have to design an image with a precise shape. This is not very flexible.

For design a image for category strip, I want to have the code to for having a left image, a small centre image repeating inself and a right image like here in vbtemplates. I actually found the code of vbtemplates:

<td width="41"><img src="images/pbleft.gif" border="0"></td>
<td width="100%" background="images/postbg.gif" valign="middle" align="center"> <a name="****"></a><font class="sf" color="#FFFFFF"><b>*****</b> - Posted: <b>**-**-****</b> at <b>**:** **</b></font></td>
<td width="41"><img src="images/pbright.gif" border="0"></td>

but in which template should I put it?



the same situation for background of posts
I want to have an upper image, a middle image repeating itself for the whole length of the post and a lower image.

please help
thank you very much