When uploading a new photo, it will get an ID autogenerated. It will be used to store metadata in Cloud Firestore and the photos in Cloud Storage.
Used to metadata that will be indexed such as location. TODO
Each original photo will be stored in /photos/{$ID}/original.jpg. For each of them there will be different sizes also stored in the same folder but with different name. Example /photos/{$ID}/40x40.jpg. While fetching the photo, if the right size is not present, it will be generated in real time and saved it.