fix

common/modules/blog/views/post-admin/_form.php

@@ -31,7 +31,7 @@ use common\modules\blog\models\Post;
 
 	    <?php if($model->preview) 
         {
-            echo Html::img(\Yii::$app->params['frontUrl'] . '/uploads/blog/' . $model->preview);
+            echo Html::img(\Yii::$app->params['frontUrl'] . $model->preview);
         } ?>
 
         <?= $form->field($model, 'file')->fileInput() ?>

console/migrations/m160210_061532_fix_file_columns.php

+<?php
+
+use yii\db\Schema;
+use yii\db\Migration;
+
+class m160210_061532_fix_file_columns extends Migration
+{
+    // Use safeUp/safeDown to run migration code within a transaction
+    public function safeUp()
+    {
+        $this->alterColumn('posts', 'preview', Schema::TYPE_STRING.'(100) DEFAULT NULL');
+        $this->alterColumn('co_content', 'preview', Schema::TYPE_STRING.'(100) DEFAULT NULL');
+        $this->alterColumn('reviews', 'photo', Schema::TYPE_STRING.'(100) DEFAULT NULL');
+    }
+
+    public function safeDown()
+    {
+        $this->alterColumn('posts', 'preview', Schema::TYPE_STRING.'(60) DEFAULT NULL');
+        $this->alterColumn('co_content', 'preview', Schema::TYPE_STRING.'(50) DEFAULT NULL');
+        $this->alterColumn('reviews', 'photo', Schema::TYPE_STRING.'(50) DEFAULT NULL');
+    }
+}