Profile: poulP

Here's a shortcode that will return an image ID given a post ID and a field slug:
[php]
function wpt_get_img_id($atts) {
  global $post, $wpdb;
  $atts = shortcode_atts([
    'postid' => 0,
    'fieldslug' => '',
  ], $atts);
  $postid = isset($atts['postid']) ? $atts['postid'] : $post->ID;
 
  $img = get_post_meta($postid, 'wpcf-' . $atts['fieldslug'], true);
 
  $query = "SELECT ID FROM {$wpdb->posts} WHERE guid='$img'";
  $id = $wpdb->get_var($query);
 
  return $id;
}
add_shortcode("get_image_id", "wpt_get_img_id");

[get_image_id postid="[wpv-post-id]" fieldslug="my-image-field"]