These are the query parameters i use...works for me when i loop through the results

    array(
    				'post_parent' => $post->ID,
    				'post_status' => 'inherit',
    				'post_type'=> 'attachment',
    				'post_mime_type' => 'image/jpeg,image/gif,image/jpg,image/png' 					
    			);

For more detail, please see official documentation for WP_Query's [status parameters][1]


  [1]: https://developer.wordpress.org/reference/classes/wp_query/#status-parameters