Buy cheap NAS boxes for each family. Backup pictures to your NAS, then use remote sync to copy pictures to the other NAS. Now everyone has the pictures locally

Buy cheap NAS boxes for each family. Backup pictures to your NAS, then use remote sync to copy pictures to the other NAS. Now everyone has the pictures locally and it’s backed up remotely. Sync the pics you like to Google for convenient access. QNAP TS-130 is $140. 4TB is about $100.