Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 36476)
+++ src/wp-includes/functions.php	(working copy)
@@ -2142,7 +2142,7 @@
 	 *                        of file types.
 	 */
 	$ext2type = apply_filters( 'ext2type', array(
-		'image'       => array( 'jpg', 'jpeg', 'jpe',  'gif',  'png',  'bmp',   'tif',  'tiff', 'ico' ),
+		'image'       => array( 'jpg', 'jpeg', 'jpe',  'gif',  'png',  'bmp',   'tif',  'tiff', 'ico', 'webp' ),
 		'audio'       => array( 'aac', 'ac3',  'aif',  'aiff', 'm3a',  'm4a',   'm4b',  'mka',  'mp1',  'mp2',  'mp3', 'ogg', 'oga', 'ram', 'wav', 'wma' ),
 		'video'       => array( '3g2',  '3gp', '3gpp', 'asf', 'avi',  'divx', 'dv',   'flv',  'm4v',   'mkv',  'mov',  'mp4',  'mpeg', 'mpg', 'mpv', 'ogm', 'ogv', 'qt',  'rm', 'vob', 'wmv' ),
 		'document'    => array( 'doc', 'docx', 'docm', 'dotm', 'odt',  'pages', 'pdf',  'xps',  'oxps', 'rtf',  'wp', 'wpd', 'psd', 'xcf' ),
@@ -2303,6 +2303,7 @@
 	'bmp' => 'image/bmp',
 	'tiff|tif' => 'image/tiff',
 	'ico' => 'image/x-icon',
+	'webp' => 'image/webp',
 	// Video formats.
 	'asf|asx' => 'video/x-ms-asf',
 	'wmv' => 'video/x-ms-wmv',
@@ -2409,7 +2410,7 @@
 function get_allowed_mime_types( $user = null ) {
 	$t = wp_get_mime_types();
 
-	unset( $t['swf'], $t['exe'] );
+	unset( $t['swf'], $t['exe'], $t['webp'] );
 	if ( function_exists( 'current_user_can' ) )
 		$unfiltered = $user ? user_can( $user, 'unfiltered_html' ) : current_user_can( 'unfiltered_html' );