Update README.md

Author: afgprogrammer

README.md

@@ -5,7 +5,7 @@ The Expense Manager Application, using Provider to manage state.
 A Flutter sample app that shows a state management approach using the Provider package and shared preferences for saving data in mobile.
 
 
-## Screenshoot
+## Screenshot
 
-<img src="assets/images/preview1.png" height="300em" /><img src="assets/images/preview2.png" height="300em" /><img src="assets/images/preview3.png" height="300em" />
+<img src="assets/images/preview1.png" height="600em" /><img src="assets/images/preview2.png" height="600em" /><img src="assets/images/preview3.png" height="600em" />