您可以从Url获取文件，如下所示：

//get the URL from your Metafield, $post is your current Post
$image = get_post_meta( $post->ID, \'_your_image_url_meta\', true );

//set up a query to search your posts table for the Url         
global $wpdb;
$query = "SELECT ID FROM $wpdb->posts WHERE guid = %s LIMIT 1";

//prepare and launch the query
$result = $wpdb->get_results( $wpdb->prepare( $query, $image ) );

//if there are results
if ( count ( $result ) > 0 ) {

    $image_id = $result[\'0\']->ID;

    //get the image data
    $image_data = get_post_meta( $image_id, \'_wp_attachment_metadata\', true );

}   

如果您在自定义字段中声明了图像的每个字段。使用以下代码获取所有post自定义字段数据；

<?php 
 while ( have_posts() ) : the_post(); 
 $postid=$post->ID;
 $all_meta_for_post = get_post_meta( $postid );    
 endwhile; 
?>