img2data.js

/*
 * Based on https://gist.github.com/583836 from http://stackoverflow.com/questions/3709391/node-js-base64-encode-a-downloaded-image-for-use-in-data-uri. 
 * Neither that gist nor this one work for me in 0.2.x or 0.3.x.
 */
var request = require('request'),
    BufferList = require('bufferlist').BufferList,
    sys = require('sys'),
    bl = new BufferList(),
    url = 'http://nodejs.org/logo.png'
;

request({uri:url, responseBodyStream: bl}, function (error, response, body) 
{
    if (!error && response.statusCode == 200) {
        var type = response.headers["content-type"];
        var prefix = "data:" + type + ";base64,";
        var base64 = new Buffer(bl.toString(), 'binary').toString('base64');
        var data = prefix + base64;
        console.log(data);
    }
});