Angular: Empty Fiddle

http://angularjs.org/

HTML

<script src="http://code.angularjs.org/angular-1.0.1.js"></script>
<div ng-controller="myCtrl">
    <div class="choose_file">
        <img src="http://upload.wikimedia.org/wikipedia/commons/a/ae/Landscape_in_the_Adirondacks_Frederic_Edwin_Church.jpg" style="height: 300px; width: 400px"></img>
        <input ng-model="someRandomValue" type="file" ng-change="trigger()" />
    </div>
</div>

CSS

body {
    padding: 10px;
}

.choose_file{
    position:relative;
    display:inline-block;    
}
.choose_file input[type="file"]{
    -webkit-appearance:none; 
    position:absolute;
    top:0; left:0;
    height: 300px;
    width: 400px;
    opacity:0; 
}

JavaScript

var myApp = angular.module('myApp', []);

myApp.controller('myCtrl', function($scope) {
    $scope.trigger = function() {
        alert("Changed");
    };
});