Center screenshot

Author: kevinsawicki

README.md

@@ -4,7 +4,9 @@ This is a desktop app that interactively and with sample code demonstrates core
 
 Use this app to see what you can do with Electron and use the source code to learn how to create a basic Electron app.
 
+<center>
 <img width="539" alt="Electron API Demos Screenshot" src="https://cloud.githubusercontent.com/assets/671378/14999808/7a9d7c6e-1140-11e6-875b-d7f5cc990e01.png">
+</center>
 
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