code: function (srcPath, options) {
          _.defaults(options || (options = {}), DEFAULT_OPTIONS);
          var separator = options.separator;
  
          var reg = new RegExp('^sprite' + separator + '.+@\\d+x\\.png$');
          return reg.test(path.basename(srcPath));
      }
docs: isSpriteSheet
  @param {String} srcPath
  @param {Object} options
  @returns {Boolean}
  @example
  var srcPath = 'test/image/sprite/sprite-logo@10x.png';
  var options = {};
  var out = isSpriteSheet(srcPath, options);
  console.log(out);
  > true