yii2 图片上传插件 yii2-widget-fileinput 上传图片后修改图片，没有预览图的问题

关键是配置下面两个参数：

initialPreview，initialPreviewConfig，都是数组，一一对应。就能在修改的时候预览缩略图了

 'initialPreview'=>[
            "http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/FullMoon2010.jpg/631px-FullMoon2010.jpg",
            "http://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Earth_Eastern_Hemisphere.jpg/600px-Earth_Eastern_Hemisphere.jpg"
        ],
        'initialPreviewAsData'=>true,
        'initialCaption'=>"The Moon and the Earth",
        'initialPreviewConfig' => [
            ['caption' => 'Moon.jpg', 'size' => '873727'],
            ['caption' => 'Earth.jpg', 'size' => '1287883'],
        ],

echo FileInput::widget([
    'name' => 'attachment_49[]',
    'options'=>[
        'multiple'=>true
    ],
    'pluginOptions' => [
        'initialPreview'=>[
            "http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/FullMoon2010.jpg/631px-FullMoon2010.jpg",
            "http://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Earth_Eastern_Hemisphere.jpg/600px-Earth_Eastern_Hemisphere.jpg"
        ],
        'initialPreviewAsData'=>true,
        'initialCaption'=>"The Moon and the Earth",
        'initialPreviewConfig' => [
            ['caption' => 'Moon.jpg', 'size' => '873727'],
            ['caption' => 'Earth.jpg', 'size' => '1287883'],
        ],
        'overwriteInitial'=>false,
        'maxFileSize'=>2800
    ]
]);