How do you sync photos with your family?
Solution 1:
Have you looked at Windows Live Skydrive? 25GB of free storage per Windows Live account, with the ability to share specific folders with specific Windows Live users...So if each family has one account, then you each have plenty of space for each family's photos...Three families, say, has 75 GB of storage combined...
25 GB of free online storage
Store, access, and share thousands of documents, photos, and Microsoft Office files on Windows Live SkyDrive. SkyDrive password-protects your files so you control who has access to them.
Easily upload and share photos and videos so you can access them online. Share one file, a whole folder, or a photo album with anyone you choose—including an entire social network
Solution 2:
Use a photo sharing service like flickr