diff --git a/preface.md b/preface.md
index 3a41caa..acad331 100644
--- a/preface.md
+++ b/preface.md
@@ -24,7 +24,7 @@
 
 | 支付宝 | 微信 |
 |:-----:|:-----:|
-|![alipay](images/donate-alipay-github-chai2010.jpg)|![weixin](images/donate-weixin-github-chai2010.jpg)|
+|![alipay](images/donate-alipay-github-chai2010-20yuan.jpg)|![weixin](images/donate-weixin-github-chai2010-20yuan.jpg)|
 
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