use kartik\widgets\FileInput
// or 'use kartikile\FileInput' if you have only installed yii2-widget-fileinput in isolation
// 使用ActiveForm 和 model綁定的單張圖片示例
echo $form->field($model, 'avatar')->widget(FileInput::classname(), [
  'options' => ['accept' => 'image/*'],
]);
// 多圖上傳示例
echo '<label class="control-label">Add Attachments</label>';
echo FileInput::widget([
  'model' => $model,
  'attribute' => 'attachment_1[]',
  'options' => ['multiple' => true]
]);
// 不綁定model的使用方法
echo '<label class="control-label">Upload Document</label>';
echo FileInput::widget([
  'name' => 'attachment_3',
]);
// 不可點擊的示例
echo '<label class="control-label">Select Attachment</label>';
echo FileInput::widget([
  'name' => 'attachment_4',
  'disabled' => true
]);

<?= $form->field($model, 'image[]')->label($label)->widget(FileInput::classname(), [
  // 'name' => 'ImgSelect',
  'language' => 'zh-CN', 
  'options' => ['multiple' => true, 'accept' => 'image/*'], 
  'pluginOptions' => [ 
    'initialPreview' => $initialPreview, 
    'initialPreviewConfig' => $initialPreviewConfig, 
    'allowedPreviewTypes' => ['image'], 
    'allowedFileExtensions' => ['jpg', 'gif', 'png'], 
    'previewFileType' => 'image', 
    'overwriteInitial' => false, 
    'browseLabel' => '選擇圖片',
    'msgFilesTooMany' => "選擇上傳的圖片數(shù)量({n}) 超過允許的最大圖片數(shù){m}！", 
    'maxFileCount' => 5,//允許上傳最多的圖片5張 
    'maxFileSize' => 2048,//限制圖片最大200kB 
    'uploadUrl' => Url::to(['/upload/image']),
    //'uploadExtraData' => ['testid' => 'listimg'], 
    'uploadAsync' => true,//配置異步上傳還是同步上傳 
  ],
  'pluginEvents' => [ 
    'filepredelete' => "function(event, key) { 
        return (!confirm('確認要刪除')); 
      }", 
    'fileuploaded' => 'function(event, data, previewId, index) { 
        $(event.currentTarget.closest("form")).append(data.response.imgfile);
      }', 
    'filedeleted' => 'function(event, key) { 
        $(event.currentTarget.closest("form")).find("#"+key).remove(); 
        return;
      }', 
  ]
]); ?>

/** 
  * 上傳圖片到臨時目錄 
  * @return string 
  * @throws \yii\base\Exception 
  */ 
 public function actionImage() 
 { 
   if (Yii::$app->request->isPost) { 
     $res = []; 
     $initialPreview = []; 
     $initialPreviewConfig = []; 
     $images = UploadedFile::getInstancesByName("UploadImage[image]"); 
     if (count($images) > 0) { 
       foreach ($images as $key => $image) { 
         if ($image->size > 2048 * 1024) { 
           $res = ['error' => '圖片最大不可超過2M']; 
           return json_encode($res); 
         } 
         if (!in_array(strtolower($image->extension), array('gif', 'jpg', 'jpeg', 'png'))) { 
           $res = ['error' => '請上傳標準圖片文件, 支持gif,jpg,png和jpeg.']; 
           return json_encode($res); 
         } 
         $dir = '/uploads/temp/'; 
         //生成唯一uuid用來保存到服務(wù)器上圖片名稱 
         $pickey = ToolExtend::genuuid(); 
         $filename = $pickey . '.' . $image->getExtension();
         //如果文件夾不存在，則新建文件夾 
         if (!file_exists(Yii::getAlias('@backend') . '/web' . $dir)) { 
           FileHelper::createDirectory(Yii::getAlias('@backend') . '/web' . $dir, 777); 
         } 
         $filepath = realpath(Yii::getAlias('@backend') . '/web' . $dir) . '/'; 
         $file = $filepath . $filename; 
         if ($image->saveAs($file)) { 
           $imgpath = $dir . $filename; 
           /*Image::thumbnail($file, 100, 100) 
             ->save($file . '_100x100.jpg', ['quality' => 80]); 
*/ 
          //  array_push($initialPreview, "<img src='" . $imgpath . "' class='file-preview-image' alt='" . $filename . "' title='" . $filename . "'>"); 
           $config = [ 
             'caption' => $filename, 
             'width' => '120px', 
             'url' => '../upload/delete', // server delete action 
             'key' => $pickey,
             'extra' => ['filename' => $filename] 
           ];
           array_push($initialPreviewConfig, $config); 
           $res = [ 
             "initialPreview" => $initialPreview, 
             "initialPreviewConfig" => $initialPreviewConfig, 
             "imgfile" => "<input name='image[]' id='" . $pickey . "' type='hidden' value='" . $imgpath . "'/>",
             'filename' => $filename,
             'imagePath' => $imgpath,
           ]; 
         }
       } 
     } 
     return json_encode($res); 
   } 
 }