How would you architect a photo sharing app to handle high scalability?

I'm going to assume that the photo sharing app shares a specific link to x amount of users who can view one single photo. 

I'm also making another assumption, once a user has uploaded a photo to xyz website, it should be stored in the backend database with an endpoint call. 

So when a user wants to share an app, they would want to create a link to share to another user, or deep link it. 

We can generate a deep link url when a user clicks on the share button, and the user would then share that link to another user. 

Once the other users taps on that link, it will be deep linked into our xyz app, parse the url link, and depending on the url components, make a fetch call to our backend, which then returns all the data needed to then open up the view which displays the images with all the fetch calls.