数组定义用法统一

Think/Image/Driver/Gd.php

@@ -50,12 +50,12 @@ class Gd{
         }
 
         //设置图像信息
-        $this->info = array(
+        $this->info = [
             'width'  => $info[0],
             'height' => $info[1],
             'type'   => image_type_to_extension($info[2], false),
             'mime'   => $info['mime'],
-        );
+        ];
 
         //销毁已存在的图像
         empty($this->im) || imagedestroy($this->im);
@@ -146,7 +146,7 @@ class Gd{
      */
     public function size(){
         if(empty($this->im)) throw new Exception('没有指定图像资源');
-        return array($this->info['width'], $this->info['height']);
+        return [$this->info['width'], $this->info['height']];
     }
 
     /**