As part of the open-source Data Transfer Project Facebook is testing allowing you to transfer you photos stored on Facebook to Google Photos.
“Four of the biggest technology companies are banding together to make it easier for users to download and transfer their data between services. Google, Microsoft, Facebook and Twitter formally announced The Data Transfer Project (DTP) today, an open-source initiative to create new tools that “enable people to freely move their information across the web,” Damien Kieran, Data Protection Officer at Twitter explained. It’s early days, but the group has published a white paper that details its vision for an easier, more flexible “data portability ecosystem.” The group says it wants an open dialogue with developers and users alike moving forward.”
More about the Data Transfer Project.