diff --git a/Makefile b/Makefile
index 0130503..fb61f3a 100644
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,8 @@
 # https://github.com/GitbookIO/gitbook
 # https://github.com/wastemobile/gitbook
 
+# http://www.imagemagick.org/
+
 default:
 	gitbook build
 
@@ -26,3 +28,8 @@ review:
 	gitbook build
 	go run zh2tw.go . .md$$ zh2tw
 
+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
+
diff --git a/cover_patch.png b/cover_patch.png
new file mode 100644
index 0000000..52af9d7
Binary files /dev/null and b/cover_patch.png differ