it would be added in your:
l/includes/templates/CUSTOM_TEMPLATE/templates/tpl_product_info_display.php file:

to pull your logo with a link to home page add:
Code:
<?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">' . zen_image($template->get_template_dir(HEADER_LOGO_IMAGE, DIR_WS_TEMPLATE, $current_page_base,'images'). '/' . HEADER_LOGO_IMAGE, HEADER_ALT_TEXT) . '</a>'; ?>
to pull just your logo add:
Code:
<?php echo zen_image($template->get_template_dir(HEADER_LOGO_IMAGE, DIR_WS_TEMPLATE, $current_page_base,'images'). '/' . HEADER_LOGO_IMAGE, HEADER_ALT_TEXT); ?>
hope this helps!