Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 18480)
+++ wp-includes/functions.php	(working copy)
@@ -2217,7 +2217,7 @@
  */
 function wp_upload_dir( $time = null ) {
 	global $switched;
-	$siteurl = get_option( 'siteurl' );
+	$siteurl = get_site_url();
 	$upload_path = get_option( 'upload_path' );
 	$upload_path = trim($upload_path);
 	$main_override = is_multisite() && defined( 'MULTISITE' ) && is_main_site();
@@ -2235,7 +2235,7 @@
 
 	if ( !$url = get_option( 'upload_url_path' ) ) {
 		if ( empty($upload_path) || ( 'wp-content/uploads' == $upload_path ) || ( $upload_path == $dir ) )
-			$url = WP_CONTENT_URL . '/uploads';
+			$url = content_url('uploads');
 		else
 			$url = trailingslashit( $siteurl ) . $upload_path;
 	}