How Photo Stream Works on an iOS Device

On an iOS device with a camera, such as the iPhone 4S with its sophisticated 8 megapixel shooter, you don’t need to do anything to use Photo Stream: every time you take a picture, iOS 5 puts that picture into the Photo Stream. That’s it. Simple.

Of course, there are limits to this simplicity: your pictures aren’t actually uploaded to Apple’s iCloud servers until your device is on a Wi-Fi network that’s connected to the Internet.

And the Photo Stream only holds 1000 pictures at most at one time, and only pictures taken within the last 30 days. So if you take more than 1000 pictures in a month, the 1001st picture replaces the first picture in the stream even if that picture is only a couple of weeks old. And regardless of how many pictures you take, the Photo Stream drops pictures more than 30 days old.