digest error loop comes up when I add ngf-max-size
<p>I made directive that show image in box.
source is below.</p>

<pre><code>angular.module('ptgui.imagebox',[
  'ngFileUpload'
])
  .directive('ptguiImagebox', ['$compile', function($compile) {
    return {
      templateUrl: 'scripts/libs/ptgui/ptgui-imagebox.html',
      restrict: 'E',
      require: 'ngModel',
      scope: {
        ngModel: "="
      },
      replace: true,
      link: function ($scope, element, attrs) {

        //이미지 선택시 취소를 누를경우 리셋되는걸 방지하기 위한 처리
        $scope.$watch('ngModel',function(newFile, oldFile){
          if (newFile) {
            $scope['ngModel'] = newFile;
          } else {
            $scope['ngModel'] = oldFile;
          }
        });

      }
    };
  }]);
</code></pre>

<p>and below is the directive template.</p>

<pre><code>&lt;div class="thumbnail" ngf-accept="'image/*'" ngf-pattern="'*.jpg,*.jpeg,*.gif,*.png'"&gt;
  &lt;img style="width: 100%;height: 100%;" ngf-thumbnail="ngModel || '/assets/images/upload.png'" &gt;
&lt;/div&gt;
</code></pre>

<p>and then I use directive like below.</p>

<pre><code>&lt;ptgui-imagebox class="col-md-3" style="width: 100px;height: 100px;" ng-model="product.image" ngf-select&gt;&lt;/ptgui-imagebox&gt;
                  &lt;div class="col-md-4 hidden-sm hidden-xs"&gt;
                    &lt;div class="file-drop-zone" ngf-select ngf-drop ng-model="product.image" ngf-drag-over-class="'file-drop-zone-over'" ngf-accept="'image/*'" ngf-pattern="'*.jpg,*.jpeg,*.gif,*.png'"&gt;
                      &lt;span class="help-block"&gt;&lt;i class="fa fa-file-picture-o"&gt; 파일을 여기로 끌어주세요.&lt;/i&gt;&lt;/span&gt;
                    &lt;/div&gt;
                  &lt;/div&gt;
</code></pre>

<p>soruce which is above don't use ngf-max-size yet. and that runs I want do.
but I have to check filesize so I add ngf-max-size="1M" like below.</p>

<pre><code>&lt;div class="file-drop-zone" ngf-select ngf-drop ng-model="product.image" ngf-drag-over-class="'file-drop-zone-over'" ngf-accept="'image/*'" ngf-pattern="'*.jpg,*.jpeg,*.gif,*.png'" # ngf-max-size="1MB"&gt;
</code></pre>

<p>but when I add that, I am able to see error which is in loop like below.
<a href="https://i.stack.imgur.com/1W8Wj.png" rel="nofollow noreferrer">enter image description here</a></p>