Hi, I'm not quite sure if this is on the right track, but it's the only reference I can find regarding your problem. I found the following code in "admin/easypopulate.php". I'm not that good with zencart yet, but it may point you in the right direction.
Especially lines 777 and 778
Cheers
J#xx
(Scott Perry)
Code:
Line #417 : $filelayout[] = "v_products_image";
Line #522 : p.products_image as v_products_image,
Line #621 : $filetemp['image_url'] = 'v_products_fullpath_image';
Line #645 : p.products_image as v_products_image,
Line #768 : // build the long full froogle image path
Line #770 : // check for a large image else use medium else use small else no link
Line #772 : $products_image = (($row['v_products_image'] == PRODUCTS_IMAGE_NO_IMAGE) ? '' : $row['v_products_image']);
Line #773 : $products_image_extension = substr($products_image, strrpos($products_image, '.'));
Line #774 : $products_image_base = ereg_replace($products_image_extension . '$', '', $products_image);
Line #775 : $products_image_medium = $products_image_base . IMAGE_SUFFIX_MEDIUM . $products_image_extension;
Line #776 : $products_image_large = $products_image_base . IMAGE_SUFFIX_LARGE . $products_image_extension;
Line #777 : if (!file_exists(DIR_FS_CATALOG_IMAGES . 'large/' . $products_image_large)) {
Line #778 : if (!file_exists(DIR_FS_CATALOG_IMAGES . 'medium/' . $products_image_medium)) {
Line #779 : $image_url = (($products_image == '') ? '' : DIR_WS_CATALOG_IMAGES . $products_image);
Line #781 : $image_url = DIR_WS_CATALOG_IMAGES . 'medium/' . $products_image_medium;
Line #784 : $image_url = DIR_WS_CATALOG_IMAGES . 'large/' . $products_image_large;
Line #787 : $row['v_products_fullpath_image'] = $image_url;
Line #1197 : 'v_products_image',
Line #1198 : // redundant image mods removed
Line #1237 : p.products_image as v_products_image,
Line #1556 : if (trim($v_products_image) == '') {
Line #1557 : $v_products_image = PRODUCTS_IMAGE_NO_IMAGE;
Line #1641 : products_image = '" . zen_db_input($v_products_image)."' ,
Line #1675 : products_image = '" . zen_db_input($v_products_image)."' ,
Hope this helps !