diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -126,7 +126,7 @@ If you use OS X system, you can install Mark Text by [**homebrew cask**](https:/
 
 > brew cask install mark-text
 
-![](https://github.com/marktext/marktext/blob/master/doc/brew-cask.jpg)
+![](https://github.com/marktext/marktext/blob/master/doc/brew-cask.gif)
 
 ### Development
 
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