node.js异步操作多,怎么写注释?

如题.
类似如下代码.返回的是一个Promise,如何明确的通过注释告知返回值?

/**
* 检测图片信息
* @param {String} imagePath 需要检测的图片路径
* @type {Object}
* @returns {Object} 通过Promise对象返回图片相关信息
*/
function identify(imagePath) {
var deferred = when.defer();
imagemagick.identify(imagePath, function (err, data) {
if (err) {
deferred.reject({
'errno' : 3,
'message' : 'file is not a image.'
});
} else {
var channel_statistics = data['channel statistics'];
deferred.resolve({
size : data.filesize,
width : data.width,
height : data.height,
type : mimeTypes[data.format],
mean : [channel_statistics.red.mean.replace(/\.[\d]+ \(.*\)/, ''), channel_statistics.green.mean.replace(/\.[\d]+ \(.*\)/, ''), channel_statistics.blue.mean.replace(/\.[\d]+ \(.*\)/, '')]
});
}
});
return deferred.promise;
}