Downloading images with node.js [closed]

I’m trying to write a script to download images using node.js. This is what I have so far:

var maxLength = 10 // 10mb
var download = function(uri, callback) {
  http.request(uri)
    .on('response', function(res) {
      if (res.headers['content-length'] > maxLength*1024*1024) {
        callback(new Error('Image too large.'))
      } else if (!~[200, 304].indexOf(res.statusCode)) {
        callback(new Error('Received an invalid status code.'))
      } else if (!res.headers['content-type'].match(/image/)) {
        callback(new Error('Not an image.'))
      } else {
        var body = ''
        res.setEncoding('binary')
        res
          .on('error', function(err) {
            callback(err)
          })
          .on('data', function(chunk) {
            body += chunk
          })
          .on('end', function() {
            // What about Windows?!
            var path="/tmp/" + Math.random().toString().split('.').pop()
            fs.writeFile(path, body, 'binary', function(err) {
              callback(err, path)
            })
          })
      }
    })
    .on('error', function(err) {
      callback(err)
    })
    .end();
}

I, however, want to make this more robust:

1. Are there libraries that do this and do this better?
2. Is there a chance that response headers lie (about length, about content type)?
3. Are there any other status codes I should care about? Should I bother with redirects?
4. I think I read somewhere that binary encoding is going to be deprecated. What do I do then?
5. How can I get this to work on windows?
6. Any other ways you can make this script better?

Why: for a feature similar to imgur where users can give me a URL, I download that image, and rehost the image in multiple sizes.