Up until now, we used the Google Plus API to get a user's public photo. All we needed was the user id to get the photo (as described here).
Now that this and the Picasa APIs are being deprecated, the only alternative I found is using the Users.photos API (as described here).
As you can see in the description, this API requires authorization, although the deprecated APIs did not, and the photo I wish to get is public. Not all of our users login with Google, but I want to be able to show everyone the public photos of the users which did login with Google. Is there any way to do this now?