First upload the image to your images/misc folder. (You can design your own signature divider image too)
Then open up your postbit or postbit_legacy template.
Find;
Code:
<!-- sig -->
<div>
__________________<br />
$post[signature]
</div>
<!-- / sig -->
and replace with this;
Code:
<!-- sig -->
<div>
<img src="images/misc/imza_ayrac.gif" border="0" alt="" /><br />
$post[signature]
</div>
<!-- / sig -->
Thats all
