ok, can anyone explain this function then, please...!

zen_image(DIR_WS_IMAGES . $random_featured_product->fields['products_image'], $random_featured_product->fields['products_name'], SMALL_IMAGE_WIDTH, SMALL_IMAGE_HEIGHT);

I understand that it builds <img> tag src, name, alt, width, hight but how does DIR_WS_IMAGES work..?

I try adding
<?php require(DIR_WS_MODULES . zen_get_module_directory(FILENAME_MAIN_PRODUCT_IMAGE));

and using

zen_image($products_image_medium, addslashes($products_name), FEATURED_PRODUCTS_WIDTH, FEATURED_PRODUCTS_HEIGHT)

but understand that this will only work on the actual product page when product id id defined.

Any ideas, I just need a push in the write direction...??