fix

common/components/activeRecordBehaviors/FileUploadBehavior.php

@@ -56,7 +56,7 @@ class FileUploadBehavior extends Behavior
             list($width, $height) = $this->thumbSize;
             try 
             {
-                Image::$driver = [Image::DRIVER_GD2];
+                Image::$driver = [Image::DRIVER_IMAGICK];
                 Image::thumbnail($this->path . $this->owner->$field, $width, $height)
                     ->save($this->getAbsolutePath().$this->folder.$filename.'.thumb.'.$this->file->extension, ['quality' => 80]);
             }