text: var gm = require('gm');
  
  var a_path = '../wechat/wechat_temp_qr/a.jpg';
  var qr_path_out = '../wechat/wechat_temp_qr/_out.png';
  gm(a_path)
      .resize(240, 240)
      .noProfile()
      .write(qr_path_out, function (err) {
          console.log(err);
          if (!err) console.log('done');
      });