Create the notebook and use the Share option to create the link to email or IM your family members who will be viewing the pictures. For family members adding pictures, make them collaborators to the notebook. Now as they have a chance, either from their phone, tablet, or computer, they can contribute to the contents.
The best part is you can add pictures to the notebook as the event goes on by just sharing them from your mobile device...perfect for those who are unable to attend. Comments can be added to the photos on the Springs and you can even tag the photos with the names of family and friends to make it easier to find all the pics of an individual.
While this isn't a service like Google Photos, it is a great way to put photos together in a way everyone you want can enjoy now and later.