gistfile1.js

var express = require('express'),
    request = require('request'),
    BufferList = require('bufferlist').BufferList,
    sys = require('sys');

var app = express.createServer(
  express.logger(),
  express.bodyDecoder()
);

app.get('/', function(req, res){
  if(req.param("url")) {
    var url = unescape(req.param("url"));
    var bl = new BufferList();
    request({uri:url, responseBodyStream: bl}, function (error, response, body) {
      if (!error && response.statusCode == 200) {
        var data_uri_prefix = "data:" + response.headers["content-type"] + ";base64,";
        var image = new Buffer(bl.toString(), 'binary').toString('base64');                                                                                                                                                                 
        image = data_uri_prefix + image;
        res.send('<img src="'+image+'"/>');
      }
    }); 
  }
});

app.listen(3010);

this https://gist.github.com/1294667 should work fine

the current example above doesn't work due to dericated modules in the request

try by putting

http://localhost:3000/?url=[url_of_your_image]