I've created a number of shared albums in Photos on my Mac and iOS devices.
When other people then view the shared albums, what data is used to access them?
I invited a person to view a shared album who had mobile data turned off on their iOS device and no wifi. However, they were able to access a shared album which surprised me as I presumed they'd need either mobile data or wifi.
The shared albums are stored locally on the iOS devices. Photos downloads optimized, smaller versions of the photos to an iPhone. iCloud Photo Sharing - Apple Support
When shared, photos taken with standard point-and-shoot cameras, SLR cameras, or iOS devices have up to 2048 pixels on the long edge. Panoramic photos can be up to 5400 pixels wide.
You need an active internet connection for the shared photos to sync to your devices in the reduced size, but then they will stay locally on the device and you can view them without an internet connection.
None of the support articles says what kind of internet connection is required for shared albums (https://support.apple.com/en-us/HT201077); for My Photo Stream the support documents state that Wi-Fi is needed, and previously this has been stated for Shared Photo Streams too (https://support.apple.com/en-us/HT203511).
As the albums are shared and stored via the cloud, I presumed users would needed 3G/4G or wifi but clearly not!
What about the first time the invited user views the shared album - do they need a connection for the device to download the optimised versions? (and then after that they are available on locally on the device).
Does Shared photos on iOS devices use data?
