Index: Gruntfile.js
===================================================================
--- Gruntfile.js	(revision 56388)
+++ Gruntfile.js	(working copy)
@@ -1029,6 +1029,7 @@
 				cwd: SOURCE_DIR,
 				src: [
 					'wp-{admin,includes}/images/**/*.{png,jpg,gif,jpeg}',
+					'wp-content/themes/**/*.{png,jpg,gif,jpeg}',
 					'wp-includes/js/tinymce/skins/wordpress/images/*.{png,jpg,gif,jpeg}'
 				],
 				dest: SOURCE_DIR