wordpress图像大小基于url

wp_get_attachment_image_src()

function fjarrett_get_attachment_id_by_url( $url ) {

    // Split the $url into two parts with the wp-content directory as the separator
    $parsed_url  = explode( parse_url( WP_CONTENT_URL, PHP_URL_PATH ), $url );

    // Get the host of the current site and the host of the $url, ignoring www
    $this_host = str_ireplace( 'www.', '', parse_url( home_url(), PHP_URL_HOST ) );
    $file_host = str_ireplace( 'www.', '', parse_url( $url, PHP_URL_HOST ) );

    // Return nothing if there aren't any $url parts or if the current host and $url host do not match
    if ( ! isset( $parsed_url[1] ) || empty( $parsed_url[1] ) || ( $this_host != $file_host ) ) {
        return;
    }

    // Now we're going to quickly search the DB for any attachment GUID with a partial path match

    // Example: /uploads/2013/05/test-image.jpg
    global $wpdb;
    $attachment = $wpdb->get_col( $wpdb->prepare( "SELECT ID FROM {$wpdb->prefix}posts WHERE guid RLIKE %s;", $parsed_url[1] ) );

    // Returns null if no attachment is found
    return $attachment[0];
}

$medium_image = wp_get_attachment_image_src( fjarrett_get_attachment_id_by_url($image_link), 'medium');

$medium_image_link = $medium_image[0];
$html = '<img src="'.$medium_image_link.'" alt="" />';