When My Photo Stream is turned on, iCloud stores your new photos for 30 days so that your computer and iOS devices have plenty of time to connect and download the photos. iCloud keeps a rolling collection of your 1000 most recent photos that were automatically uploaded by My Photo Stream.
If you prefer to choose which photos from your iPhoto library are added to My Photo Stream, you can turn off automatic uploading and add photos to My Photo Stream manually.
Photos taken with an iOS device with My Photo Stream turned on, photos saved to the device’s Camera Roll, and photos imported to your iPad using the Apple Camera Connection Kit are uploaded automatically. You can’t manually add photos from your device’s Camera Roll to My Photo Stream.
Note: Only image files in JPEG, PNG, TIFF, or RAW format can be uploaded to My Photo Stream.
Choose iPhoto > Preferences, and then click iCloud.
Deselect the Automatic Upload checkbox.
You can manually add photos from your iPhoto library to My Photo Stream whether automatic uploading is on or off.
Select one or more photos.
Do one of the following:
Click the Share button in the toolbar, click iCloud, and click My Photo Stream.
Click the Add To button in the toolbar, click iCloud, and click My Photo Stream
Drag the photos to iCloud in the Source list, and click My Photo Stream.
Choose Share > iCloud, and click My Photo Stream.
The photos are uploaded to My Photo Stream and can be viewed on all the devices in your photo stream.
iCloud can store up to 1000 photos from My Photo Stream. When you add a new photo to My Photo Stream after you reach the 1000-item limit, the oldest photo is removed.
Photos remain in iCloud for 30 days, and are then removed automatically.
You can delete individual photos from My Photo Stream.