Oops... That a different story.. I edit the includes/templates/template_default(or your template folder)/common/tpl_footer.php
file and change the bottom of the file to look like:
<!--bof- site copyright display -->
<div id="siteinfoLegal" class="legalCopyright"><?php echo FOOTER_TEXT_BODY; ?></div>
<!--eof- site copyright display -->
<div align="center"><img src="yourimage.gif"></div>
<?php
} // flag_disable_footer
?>

Marg