Apple is shutting down its My Photo Stream service on July 26. My Photo Stream is a Wi-Fi syncing service that can copies your photos between your Apple devices so that they can accessed on any of them without having to pay for a cloud service. The difference between iCloud and My Photo Stream is that iCloud is cloud-based and offers limited free storage because it is stored on Apple’s servers. To store or sync your entire photo collection, you’d have to use one of the paid iCloud plans.
This decision comes a couple of years after the Google Photos free unlimited plan was eliminated. If you’d rather not be roped into paid cloud storage, i’d recommend Syncthing. Syncthing enables you to sync files (not just photos) between your devices (whether or not they are Apple) for free. It works over the Internet, and it can sync your files offline using your devices’ built-in local networking capabilities. It will protect your data with encryption and is fully open source, which is important to transparency and increases the likelihood of developers spotting bugs and fixing them.
It is available for Linux, MacOS, Windows, and Android, but not iOS (yet).