Apple is shutting down its cloud-based service My Photo Stream on July 26th. This means that if you use this service to store or share images on any of your Apple products, you cannot rely on your photos being saved. Although the switch-off is set for late July, images will not be saved from the 30 days before this date.
My Photo Stream has been around since 2011, which is admittedly a long time in technological terms. However, there are people who rely on this service still to share photos between devices (my mother, for example!).