Photo Stream is a feature that allows users to automatically upload and share photos across their devices. When you take a picture on one device, it instantly appears on all other devices linked to the same account, making it easy to access your latest memories. This service is part of iCloud, which is Apple's cloud storage solution. Users can view, download, and share their photos with friends and family. Photo Stream keeps your images organized and ensures that you never miss a moment, as it stores your most recent photos for 30 days before they are removed from the stream.