当我尝试在Node.js中使用GraphicsMagick时出现错误

Question

我在节点代码中使用graphicsMagick。

   var tokenvalue;
   tokenvalue = randomstring.generate({
       length: 16,
       numeric: true,
       letters: true,
       special: false,
    });
    var image = tokenvalue + '.png';
    var pathToFile = path.join(__dirname, req.file.path)
    , pathToSnapshot =path.join(__dirname,pro_root_path+'public/uploads/thumbnail/'+image);
        gm(pathToFile).thumb(150, // Width
                    150, // Height
             pathToSnapshot, // Output file name
             40, // Quality from 0 to 100
             function (error, stdout, stderr, command) {
                   if (!error) {
                   console.log("command");
                   }
                   else {
                   console.log(error);
                   }
                  });

出现这样的错误：

Error: Could not execute GraphicsMagick/ImageMagick: gm "identify" "-ping" "-format" "%wx%h" "E:\vishnu\Thumbnail View for doc\folder\app\public\uploads\docs\tmp\mypdf.pdf" this most likely means the gm/convert binaries can't be found
    at ChildProcess.<anonymous> (E:\vishnu\Thumbnail View for doc\folder\node_modules\gm\lib\command.js:232:12)
    at emitOne (events.js:116:13)
    at ChildProcess.emit (events.js:211:7)
    at ChildProcess.cp.emit (E:\vishnu\Thumbnail View for doc\folder\node_modules\gm\node_modules\cross-spawn\lib\enoent.js:36:37)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:198:12)

我已经完成了搜索并为Windows安装了图形魔术。但是即使出现错误。我该怎么办。我需要将pdf转换为缩略图（任何格式的jpeg，png，gif）是否还有其他npm来解决此问题。