const server = HTTP.createServer((req,res) => {
init(req,res,staticFileServer_CONFIG);
});

server.listen(staticFileServer_CONFIG.port,staticFileServer_CONFIG.host,() => {
console.log(Image Server running at http://${staticFileServer_CONFIG.host}:${staticFileServer_CONFIG.port}/);
});

// 当前支持的 文件类型，你可以不断扩充。
var MIME_TYPES = {
'.txt': 'text/plain','.md': 'text/plain','': 'text/plain','.html': 'text/html','.css': 'text/css','.js': 'application/javascript','.json': 'application/json','.jpg': 'image/jpeg','.png': 'image/png','.gif': 'image/gif'
};

MIME_TYPES['.htm'] = MIME_TYPES['.html'];

var httpEntity = {
contentType: null,data: null,getHeaders: function (EXPIRY_TIME) {
// 返回 HTTP Meta 的 Etag。可以了解 md5 加密方法
var hash = CRYPTO.createHash('md5');
//hash.update(this.data);
//var etag = hash.digest('hex');

return { 
  'Content-Type': this.contentType,'Content-Length': this.data.length,//'Cache-Control': 'max-age=' + EXPIRY_TIME,//'ETag': etag 
}; 

}
};

function init(request,response) {
var args = url.parse(request.url).query,//arg => name=a&id=5
params = querystring.parse(args);

if (params.url) {
getRemoteImg(request,response,params);
} else {
load_local_img(request,params);
}
}

// 加载远程图片
function getRemoteImg(request,params) {
var imgData = ""; // 字符串
var size = 0;
var chunks = [];

Step(function () {
HTTP.get(params.url,this);
},function (res) {
var maxLength = 10; // 10mb
var imgData = "";
if (res.headers['content-length'] > maxLength 1024 1024) {
server500(response,new Error('Image too large.'));
} else if (!~[200,304].indexOf(res.statusCode)) {
server500(response,new Error('Received an invalid status code.'));
} else if (!res.headers['content-type'].match(/image/)) {
server500(response,new Error('Not an image.'));
} else {
// res.setEncoding("binary"); //一定要设置response的编码为binary否则会下载下来的图片打不开
res.on("data",function (chunk) {
// imgData+=chunk;
size += chunk.length;
chunks.push(chunk);
});

    res.on("end",this); 
  } 

},function () {  
  imgData = Buffer.concat(chunks,size); 

  var _httpEntity = Object.create(httpEntity); 
  _httpEntity.contentType = MIME_TYPES['.png']; 
  _httpEntity.data = imgData; 
  // console.log('imgData.length:::' + imgData.length) 
  // 缓存过期时限 
  var EXPIRY_TIME = (staticFileServer_CONFIG.file_expiry_time * 60).toString(); 
  response.writeHead(200); 
  response.end(_httpEntity.data); 
} 

);

}

// 获取本地图片
function load_local_img(request,params) {
if (PATH.extname(request.url) === '') {
// connect.directory('C:/project/bigfoot')(request,function(){});
// 如果 url 只是 目录 的，则列出目录
console.log('如果 url 只是 目录 的，则列出目录');
server500(response,'如果 url 只是 目录 的，则列出目录@todo');
} else {
var pathname = require('url').parse(request.url).pathname;
// 如果 url 是 目录 + 文件名 的，则返回那个文件
var path = staticFileServer_CONFIG.site_base + pathname;

Step(function () { 
  console.log('请求 url :' + request.url + ',path : ' + pathname); 
  fs.exists(path,function (path_exists,err) { 
  if (err) { 
    server500(response,'查找<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>失败！'); 
    return; 
  } 
  if (path_exists) { 
    fs.readFile(path,this); 
  } else { 
    response.writeHead(<a href="/tag/404/" target="_blank" class="keywords">404</a>,{ 'Content-Type': 'text/plain;charset=utf-8' }); 
    response.end('找不到 ' + path + '\n'); 
  } 
},function (err,data) { 
  if (err) { 
    server500(response,'读取<a href="/tag/wenjian/" target="_blank" class="keywords">文件</a>失败！'); 
    return; 
  } 
  var extName = '.' + path.split('.').pop(); 
  var extName = MIME_TYPES[extName] || 'text/plain'; 

  var _httpEntity = Object.create(httpEntity); 
  _httpEntity.contentType = extName; 
  var buData = new Buffer(data); 
  //images(buData).height(100); 

  var newImage; 

  if (params.w && params.h) { 
    newImage = images(buData).resize(Number(params.w),Number(params.h)).encode("jpg",{ operation: 50 }); 
  } else if (params.w) { 
    newImage = images(buData).resize(Number(params.w)).encode("jpg",{ operation: 50 }); 
  } else if (params.h) { 
    newImage = images(buData).resize(null,{ operation: 50 }); 
  } else { 
    newImage = buData; // 原图 
  } 

  _httpEntity.data = newImage; 

  // 命中缓存，Not Modified返回 304 
  if (request.headers.hasOwnProperty('if-none-match') && request.headers['if-none-match'] === _httpEntity.ETag) { 
    response.writeHead(304); 
    response.end(); 
  } else { 
    // 缓存过期时限 
    var EXPIRY_TIME = (staticFileServer_CONFIG.file_expiry_time * 60).toString(); 

    response.writeHead(200,_httpEntity.getHeaders(EXPIRY_TIME)); 
    response.end(_httpEntity.data); 
  } 
}); 

}
}
function server500(response,msg) {
console.log(msg);
response.writeHead(404,{ 'Content-Type': 'text/plain;charset=utf-8' });
response.end(msg + '\n');
}
加水印也是可以的。例子如下。
var images = require('images');
var path = require('path');
var watermarkImg = images(path.join(dirname,'path/to/watermark.ext'));
var sourceImg = images(path.join(dirname,'path/to/sourceImg.ext'));
var savePath = path.join(__dirname,'path/to/saveImg.jpg');

// 比如放置在右下角，先获取原图的尺寸和水印图片尺寸
var sWidth = sourceImg.width();
var sHeight = sourceImg.height();
var wmWidth = watermarkImg.width();
var wmWidth = watermarkImg.height();

images(sourceImg)
// 设置绘制的坐标位置，右下角距离 10px
.draw(watermarkImg,sWidth - wmWidth - 10,sHeight - wmHeight - 10)
// 保存格式会自动识别
.save(savePath);