diff --git a/Makefile b/Makefile
index bc36739..87cf96f 100644
--- a/Makefile
+++ b/Makefile
@@ -37,8 +37,11 @@ cover:
 	composite  cover_patch.png cover_bgd.png cover.jpg
 	convert    -resize 1800x2360! cover.jpg  cover.jpg
 	convert    -resize 200x262!   cover.jpg  cover_small.jpg
+	convert    -resize 400x524!   cover.jpg  cover_middle.jpg
 	convert    -quality 75% cover.jpg        cover.jpg
 	convert    -quality 75% cover_small.jpg  cover_small.jpg
+	convert    -quality 75% cover_middle.jpg cover_middle.jpg
 	convert    -strip       cover.jpg        cover.jpg
 	convert    -strip       cover_small.jpg  cover_small.jpg
+	convert    -strip       cover_middle.jpg cover_middle.jpg
 
diff --git a/README.md b/README.md
index e55b3b6..e310163 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Go語言聖經 [《The Go Programming Language》](http://gopl.io) 中文版本
 - 在線預覽：http://golang-china.github.io/gopl-zh
 - 原版官網：http://gopl.io
 
-[![](cover_small.jpg)](https://github.com/golang-china/gopl-zh)
+[![](cover_middle.jpg)](https://github.com/golang-china/gopl-zh)
 
 
 ### 從源文件構建
diff --git a/cover.jpg b/cover.jpg
index b14ac99..e17af9e 100644
Binary files a/cover.jpg and b/cover.jpg differ
diff --git a/cover_middle.jpg b/cover_middle.jpg
new file mode 100644
index 0000000..3454aef
Binary files /dev/null and b/cover_middle.jpg differ
diff --git a/cover_patch.png b/cover_patch.png
index 52af9d7..9693baf 100644
Binary files a/cover_patch.png and b/cover_patch.png differ
diff --git a/cover_small.jpg b/cover_small.jpg
index ed6818e..9602015 100644
Binary files a/cover_small.jpg and b/cover_small.jpg differ
diff --git a/preface.md b/preface.md
index 441b928..5492595 100644
--- a/preface.md
+++ b/preface.md
@@ -9,7 +9,7 @@ Go語言聖經 [《The Go Programming Language》](http://gopl.io) 中文版本
 - 在線預覽：http://golang-china.github.io/gopl-zh
 - 原版官網：http://gopl.io
 
-[![](cover_small.jpg)](https://github.com/golang-china/gopl-zh)
+[![](cover_middle.jpg)](https://github.com/golang-china/gopl-zh)
 
 **版權聲明：** <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>。