Add Image Attributes Pro features to Classified Listing.

IAP: Compatibility with Classified Listings Plugin

/**
 * Add Image Attributes Pro features to Classified Listing.
 * 
 * Note: Classified Listing plugin hides gallery images from the WordPress Media Library. However these images are simply hidden
 * and the Bulk Updater of Image Attributes Pro will be able to discover them. 
 * If you wish to display them in the Media Library, please add this snippet to 
 * your functions.php as well - https://wordpress.org/support/topic/about-adding-gallery-images-to-media-library/#post-16643698
 * 
 * @link https://imageattributespro.com
 * @link https://wordpress.org/plugins/classified-listing/
 */
if ( defined( 'IAFFPRO_VERSION_NUM' ) ) {

	/**
	 * Add Image Attributes Pro bulk actions to classifieds listings.
	 * @link https://imageattributespro.com/add-bulk-action-to-any-post-type/
	 */
	add_filter( 'bulk_actions-edit-rtcl_listing', 'iaffpro_add_bulk_action_update_image_attributes_to_posts' );
	add_filter( 'handle_bulk_actions-edit-rtcl_listing', 'iaffpro_handle_posts_bulk_action_update_image_attributes', 10, 3 );

	// Add Image Attributes Pro meta box into Classifieds listing editor.
	add_action( 'add_meta_boxes_rtcl_listing', 'iaffpro_add_meta_box_posts_pages' );

	// Update attributes of images in Classifieds Gallery while updating attributes of listing.
	add_action( 'iaffpro_after_update_attributes_in_post', 'iaffpro_cl_update_classifieds_gallery_image_attributes' );

	/**
	 * Update attributes of images in Classifieds Gallery while updating attributes of listing.
	 * 
	 * @param $post_id (integer) ID of the post that is being updated in iaffpro_update_attributes_in_post_by_post_id()
	 */
	function iaffpro_cl_update_classifieds_gallery_image_attributes( $post_id ) {
		
		$gallery_images = get_post_meta( $post_id, '_rtcl_attachments_order', true );

		foreach( $gallery_images as $image ) {
			// Generate image attributes
			$attributes = iaffpro_generate_image_attributes( $image, $post_id, true );

			// Update image attributes in media library
			iaffpro_update_image( $image, $attributes, true );
		}
	}
}

To unhide images added to listing gallery from the Media Library, add this to functions.php

remove_action( 'ajax_query_attachments_args', [ \Rtcl\Controllers\Hooks\ActionHooks::class, 'remove_ajax_query_attachments_args' ] );
remove_action( 'load-upload.php', [ \Rtcl\Controllers\Hooks\ActionHooks::class, 'remove_attachments_load_media' ] );

Source: https://wordpress.org/support/topic/about-adding-gallery-images-to-media-library/#post-16643698