Displaying Product Images Not 100% Working?

Hiya everyone,

Ive been working on the pristlist module so that it now shows the product image on the list, ive done it all upto it displaying that products image im using

zen_image(DIR_WS_IMAGES . $listing->fields['products_image'], $listing->fields['products_name'], IMAGE_PRODUCT_LISTING_WIDTH, IMAGE_PRODUCT_LISTING_HEIGHT)

which details for each product the no_picture any ideas on how to fix this? below is how it lists the product name if that helps

<td class="prdPL"><div><a href="' . zen_href_link($handler_page, 'products_id=' . $products_id) . '" target="_blank">' . $cats[$cat_index][$prod_index]['products_name'] . '</a></div></td>

Thanks

any ideas anyone? i need to get this done for a client by the morning and need to sleep :)