Index: wp-admin/includes/file.php
===================================================================
--- wp-admin/includes/file.php	(revision 19264)
+++ wp-admin/includes/file.php	(working copy)
@@ -461,10 +461,6 @@
 
 	$filename = wp_unique_filename( $uploads['path'], $file['name'], $unique_filename_callback );
 
-	// Strip the query strings.
-	$filename = str_replace('?','-', $filename);
-	$filename = str_replace('&','-', $filename);
-
 	// Move the file to the uploads dir
 	$new_file = $uploads['path'] . "/$filename";
 	if ( false === @ rename( $file['tmp_name'], $new_file ) ) {
Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 19264)
+++ wp-admin/includes/media.php	(working copy)
@@ -588,7 +588,7 @@
 		// Set variables for storage
 		// fix file filename for query strings
 		preg_match('/[^\?]+\.(jpg|JPG|jpe|JPE|jpeg|JPEG|gif|GIF|png|PNG)/', $file, $matches);
-		$file_array['name'] = basename($matches[0]);
+		$file_array['name'] = urldecode( basename( $matches[0] ) );
 		$file_array['tmp_name'] = $tmp;
 
 		// If error storing temporarily, unlink
Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 19264)
+++ wp-includes/formatting.php	(working copy)
@@ -714,7 +714,7 @@
  */
 function sanitize_file_name( $filename ) {
 	$filename_raw = $filename;
-	$special_chars = array("?", "[", "]", "/", "\\", "=", "<", ">", ":", ";", ",", "'", "\"", "&", "$", "#", "*", "(", ")", "|", "~", "`", "!", "{", "}", chr(0));
+	$special_chars = array("?", "[", "]", "/", "\\", "=", "<", ">", ":", ";", ",", "'", "\"", "&", "$", "#", "*", "(", ")", "|", "~", "`", "!", "{", "}", "%", "+", chr(0));
 	$special_chars = apply_filters('sanitize_file_name_chars', $special_chars, $filename_raw);
 	$filename = str_replace($special_chars, '', $filename);
 	$filename = preg_replace('/[\s-]+/', '-', $filename);