1 files changed, 10 insertions, 2 deletions

diff --git a/picture.go b/picture.go
index 97e72a6..decc37d 100644
--- a/picture.go
+++ b/picture.go
@@ -1,3 +1,11 @@
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX files. Support reads and writes XLSX file generated by
+// Microsoft Excel™ 2007 and later. Support save file without losing original
+// charts of XLSX. This library needs Go version 1.8 or later.
+//
+// Copyright 2016 - 2018 The excelize Authors. All rights reserved. Use of
+// this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
 package excelize
 
 import (
@@ -86,10 +94,10 @@ func (f *File) AddPicture(sheet, cell, picture, format string) error {
 	}
 	ext, ok := supportImageTypes[path.Ext(picture)]
 	if !ok {
-		return errors.New("Unsupported image extension")
+		return errors.New("unsupported image extension")
 	}
 	readFile, err := os.Open(picture)
-	if err!=nil{
+	if err != nil {
 		return err
 	}
 	defer readFile.Close()