iCloud is all about making it easier for your iOS mobile devices to share data online, and between themselves and your Mac or PC. A key part of this is the Photo Stream feature, which synchronises your 1,000 most recent images across all of your iOS devices, as well as with Apple TV, and iPhoto 11, version 9.2 or later, installed on a regular Mac.
Images are automatically retired from the stream after 30 days, even if you don't have 1,000 in the queue. They won't be removed from the device that originally took them, though, or any other device that has downloaded them from iCloud.
Images in your photo stream don't count against the 5GB limit of your free iCloud account, which is good news, as few of us want to think about capacity issues when we're shooting the family on holiday -- shooting photos, that is.
Set up photo synchronisation
Like all of iCloud's features, Photo Stream is activated on your iOS 5 device through 'settings' and then 'iCloud'. Tap 'Photo Stream' and set the slider to 'on'. A complex, 5-megapixel shot from the iPhone's camera can top 2.5MB, so, to save hammering your 3G connection, Photo Stream only works when you're connected to a Wi-Fi network.
Activate the other half of the Photo Stream equation on your Mac. Go to 'system preferences' and then 'iCloud' and then check the box beside 'Photo Stream'. The find the matching setting in iPhoto at 'preferences' and then 'Photo Stream'. Check at least the boxes to 'enable Photo Stream' and allow 'automatic import'. Now, whenever you shoot an image on your iPhone, it will be automatically written to your iPhoto library the next time you start it up with your Mac connected to the Net.
With Photo Stream now working, each of your registered devices will watch iCloud for updates and automatically import them. iPhoto will automatically keep a copy of everything that appears in the Stream, but, on iOS devices, you need to pick and choose which to keep.
To do this, open the Photos app and tap back to the 'albums' menu. Tap into the new Photo Stream album and scroll through your images. When you find one you want to transfer to this device, tap it, and then tap the shortcut button and select 'save to camera roll'.
Because iPhoto, iTunes and iMovie control the Mac's media browser, which is used by many of Apple's consumer apps and several others from third parties, your Photo Stream will also show up in Pages, Keynote and Numbers, both on the Mac and your iOS device.
On the Mac, open the media browser, click 'photos' and select either the monthly Photo Stream entry that appears in the iPhoto section or, if you need an image from an earlier month, pick 'events', followed by the relevant month.
On an iOS device, tap the toolbar's media button and select Photo Stream from the list of sources, where you will find each of the images synchronised from your other devices.
Photo Stream works in both directions, so you can just as easily use it to upload images from your regular camera to an iOS device via iPhoto. Import your images either by dragging them into the iPhoto library, at which point you'll find them by clicking 'last import' in the sidebar, or by clicking 'file' and then 'import to library' and selecting your source media.
Drag the images onto the Photo Stream entry in the sidebar to send them up to iCloud and make them visible on your iOS device.