By default, photos in your Photo Stream are automatically imported into your iPhoto library. If you prefer to manually import photos from Photo Stream into your iPhoto library, you can turn off automatic imports in iPhoto preferences.
To save Photo Stream photos to an iOS device, you must save them to the device’s Camera Roll or to an album.
To turn off automatic imports from Photo Stream to your iPhoto library:
Choose iPhoto > Preferences, and then click Photo Stream.
Deselect the Automatic Import checkbox.
To manually import Photo Stream photos to your iPhoto library:
In iPhoto, drag one or more photos from Photo Stream view to Photos in the Source list (on the left).
To import Photo Stream photos to an iOS device:
On your device’s Home screen, tap Photos.
Tap Photo Stream, and then tap the arrow icon in the upper-right corner.
Tap the photo or photos you want to import, and then do one of the following:
To save to your device’s Camera Roll, tap Save.
To save to an album on your device, tap Add To, and then tap “Add to Existing Album” or “Add to New Album.” Select an album, or type a name for a new album, and tap Save.
Note: If iPhoto automatically imports a Photo Stream photo that was originally uploaded from a different iPhoto library, or from an Aperture library, iPhoto adds the photo to the Event that matches the one in the original library. If a matching Event isn’t in the destination library, iPhoto creates a new Event with the same name.