help with zc image function

[tony_sar]

I need to add ajax zoom effect to my image .. however, i have a bit of problem doing so , due to lack of understanding zc function .

need to add additional element called longdesc to <img> tag.
this element should contain path to large image.

currently trying to add this zoom effect to product all listing .
code that needed to be modified is :

    $display_products_image = '<a href="' . zen_href_link(zen_get_info_page($products_all->fields['products_id']), 'cPath=' . zen_get_generated_category_path_rev($products_all->fields['master_categories_id']) . '&products_id=' . $products_all->fields['products_id']) . '">' . zen_image(DIR_WS_IMAGES . $products_all->fields['products_image'], $products_all->fields['products_name'], IMAGE_PRODUCT_ALL_LISTING_WIDTH, IMAGE_PRODUCT_ALL_LISTING_HEIGHT) . '</a>' . str_repeat('<br clear="all" />', substr(PRODUCT_ALL_LIST_IMAGE, 3, 1)); 

so i need to add $parama=longdesc = zen_images() after IMAGE_PRODUCT_ALL_LISTING_HEIGHT . but i have no idea how . tried many ways but ended up with all kinda problems.

any information would be appreciate.

thanks.