Index: /twentyten/functions.php
===================================================================
--- /twentyten/functions.php	(revision 4279)
+++ /twentyten/functions.php	(revision 4325)
@@ -103,6 +103,4 @@
 	// Your changeable header business starts here
 	define( 'HEADER_TEXTCOLOR', '' );
-	// No CSS, just IMG call. The %s is a placeholder for the theme template directory URI.
-	define( 'HEADER_IMAGE', '%s/images/headers/path.jpg' );
 
 	// The height and width of your custom header. You can hook into the theme's own filters to change these values.
@@ -176,4 +174,10 @@
 		)
 	) );
+
+	// Use a consistent random default header
+	global $_wp_default_headers;
+	$header_names = array_keys( $_wp_default_headers );
+	$header_key = crc32( site_url() ) % count( $_wp_default_headers );
+	define( 'HEADER_IMAGE', $_wp_default_headers[$header_names[$header_key]]['url'] );
 }
 endif;