Update README.md

Author: nuarz71

README.md

@@ -5,7 +5,11 @@
 
 Slide button library for android, we hope this library is useful and easy to customize as you needed.
 
-<img src="/previews/sliding_button_sample_preview.gif" alt="Preview" style="zoom:28%;" />
+### Sample Preview
+
+<center style="background:#FCFCFC;">
+<img src="/previews/sliding_button_sample_preview.gif" alt="Preview" width="300" />
+</center>
 
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@@ -30,7 +34,6 @@ repositories {
 
 
 
-
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 # How To Use