This is really just a quick demo of how to create a simple service for snapshotting a web page on Heroku. In reality, you’d want this running behind some kind of password or auth so somebody doesn't slam it with requests.
First, clone this repo!
Then, create your Heroku app using the heroku-buildpack-multi buildpack (this is needed to run both NodeJS and PhantomJS):
$ heroku create --stack cedar --buildpack https://github.com/ddollar/heroku-buildpack-multi.git
And then simply push it to Heroku!
$ git push heroku master
Now you can head on over to your browser and point it to your app, e.g. http://.herokuapp.com/http%3A%2F%2Fheroku.com.png to see a snapshot of heroku.com