I feel like react-rails (https://github.com/reactjs/react-rails https://github.com/reactjs/react-rails) is basically perfect for this. You just make the photo u

I feel like react-rails (https://github.com/reactjs/react-rails https://github.com/reactjs/react-rails) is basically perfect for this. You just make the photo upload its own react component and render it as normal from your rails view. You basically encapsulate the small bit of complex state into a component and it doesn't infect the rest of your app with SPA.