修复下载远程图片bug

src/Tools/Drawer.php

@@ -49,7 +49,7 @@ class Drawer
         $url = $this->parseUrl($url);
         // excel画图中下载图片时对图片名做urlencode处理,防止中文名不能正常画图片的bug
         $filename = trim(pathinfo($url, PATHINFO_FILENAME));
-        $ext = $this->getImgExt($url);
+        $ext = strtolower(pathinfo($url, PATHINFO_EXTENSION));
         $filename = "$filename.$ext";
 
         $path = $this->rootPath . '/download/images/' . ($path ?: $this->savePath);