text: ﻿var gm = require('gm');
  var dirpath = 'images/';
  var imgname = 'download-logo.png';
  var tmppath = 'tmp/';
  
  gm(dirpath + imgname) 
      .setFormat('gif') 
      .write(tmppath + 'New_' + imgname, function (err) {
          if (err)
              throw err;
          console.log('done');
  });