File uploading problem in related models about yii2-relation-trait

[mootensai]

I use this widget
http://demos.krajee.com/widget-details/fileinput
https://github.com/kartik-v/yii2-widget-fileinput
I use that like this

<?= $form->field($model, 'image_path')->widget(FileInput::className(),[
        'model' => $model,
        'attribute' => 'image_path',
        'options' => [
            'placeholder' => 'Gambar',
            'data-show-preview' => false
        ],
        'pluginOptions' => [
            'showPreview' => true,
            'showUpload' => false,
            'allowedFileExtensions' => ['jpg', 'png'],
            'maxFileSize' => 12 * 1024
        ]
    ]);
    ?>