Update README.md

Author: pisalcoding

README.md

@@ -1,6 +1,6 @@
 # TopAlerter
-A simple sample implementation of Top Alert Dialog. This is right for you if you don't want to use a library.
-
-
-DEMO:
-![Alt Text](img_demo.gif)
+A simple sample implementation of Top Alert Dialog. 
+This is right for you if you don't want to use a library.
+<div style="text-align:center; width: 100%;">
+  <img src="img_demo.gif" width="300" height="auto" align="center"> 
+</div>