You accomplished a lot in this chapter. You learned useful methods for updating individual photos in a list. Then, you learned how to use Elm ports and subscriptions along with WebSockets to update the photo feed in real time.
You now have an amazing base of knowledge and experience to write your own Elm applications. You can build upon that base to start investigating more advanced concepts. Real-world applications are typically larger than a couple hundred lines of code. In the next chapter, you will learn techniques for organizing code and managing larger codebases.