If you're looking for a Google photos alternative, check out Canon Irista: https://www.irista.com/pricing 15 GB is free, 100 GB is 2 Euros/month, you can share albums/photos AND IT'S NOT GOOGLE. Not open source, but so far I like it!
@istvan I know of #Cryptee. I mainly.use it for documents but it also lets you upload photos. It is open source and encrypts your data. Free storage is not that much I think but can also be upgraded for a price. But no sharing though. At crypt.ee