Do not save duplicate images

Adding the same image should create a drawing referencing the
already stored copy of the image.

Closes #359

1 files changed, 2 insertions, 1 deletions

diff --git a/README.md b/README.md
index 84ddde0..7774a50 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,8 @@
 
 ## Introduction
 
-Excelize is a library written in pure Go and 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. The full API docs can be seen using go's built-in documentation tool, or online at [godoc.org](https://godoc.org/github.com/360EntSecGroup-Skylar/excelize) and [docs reference](https://xuri.me/excelize/).
+Excelize is a library written in pure Go providing a set of functions that allow you to write to and read from XLSX files. Supports reading and writing XLSX file generated by Microsoft Excel™ 2007 and later.
+Supports saving a file without losing original charts of XLSX. This library needs Go version 1.8 or later. The full API docs can be seen using go's built-in documentation tool, or online at [godoc.org](https://godoc.org/github.com/360EntSecGroup-Skylar/excelize) and [docs reference](https://xuri.me/excelize/).
 
 ## Basic Usage