[WoodMart Additional Variation Images]

import-woodmart-additional-variation-images.md

function wpai_woodmart_gallery_image_imported( $post_id, $att_id, $filepath, $is_keep_existing_images = '' ) {
	$product = wc_get_product( $post_id );
	if ( ! $product ) return;

	$variationID_first = get_post_meta( $product->get_id(), wpai_woocommerce_add_on\XmlImportWooCommerceService::FIRST_VARIATION, TRUE );
	if ( $product->is_type( 'variation' ) || ! empty( $variationID_first ) ) {
		if ( empty( $variationID_first ) ) {
			$variationID = $product->get_id();
			$parent      = $product->get_parent_id();
		} else {
			$variationID = $variationID_first;
			$parent      = $product->get_id();
		}

		$gallery = get_post_meta( $parent, 'woodmart_variation_gallery_data', true );
		if ( empty( $gallery ) ) {
			$gallery = array();
		} else {
			$gallery = maybe_unserialize( $gallery );
		}

		if ( array_key_exists( $variationID, $gallery ) ) {
			$existing = explode( ',', $gallery[ $variationID ] );
			$existing[] = $att_id;
			$gallery[ $variationID ] = implode( ',', $existing );
		} else {
			$gallery[ $variationID ] = $att_id;
		}
		
		// filter out featured images from variation galleries.
		$gallery[ $variationID ] = implode( ',', array_diff( explode( ',', $gallery[ $variationID ] ), get_post_meta( $variationID, '_thumbnail_id', false ) ) );

		update_post_meta( $variationID, 'wd_additional_variation_images_data', $gallery[ $variationID ] );
		update_post_meta( $parent, 'woodmart_variation_gallery_data', $gallery );
	}
}
add_action( 'pmxi_gallery_image', 'wpai_woodmart_gallery_image_imported', 10, 4 );

@trey8611 THANKS! You saved my life.

@NerQuiLes you should update the line that @dauclair951 mentioned above to make it work.

@asify3409 it works without adding any custom field. Just paste the code in your functions.php