OnClick change Images AngularJS

<div ng-app="FormApp" ng-controller="myController" max-width="1150px;" width="1150px;" >

    <input ng-show="ShowDown" type="image" style="width:250px; height:40px;" src="~/Content/Images/contactShow.png" ng-click="ShowHide()"/>

    <input ng-show="ShowUp" type="image" style="width:250px; height:40px;" src="~/Content/Images/contactHide.png" ng-click="ShowHide()" />

</div>

<script type="text/javascript">

    var app = angular.module('FormApp', [])

    app.controller('myController', function ($scope) {

        $scope.ShowDown = true;

        $scope.ShowUp = false;

        $scope.ShowHide = function () {

            $scope.ShowDown = $scope.ShowDown ? false : true;

            $scope.ShowUp = $scope.ShowUp ? false : true;

        }

    });

</script>