1. First, photos uploaded to My Photo Stream or Shared Photo Streams do not count against your iCloud storage.
2. The photos you upload to My Photo Stream are stored in iCloud for 30 days to give your devices plenty of time to connect and download them.
3. When you delete a photo from Photo Stream on one device, iCloud will automatically delete it from the Photo Stream album or view on your other devices. Learn more about deleting photos.
4. If you are the owner of a shared photo stream, you can delete photos from the stream the same way you delete any other photos from your iOS device or Mac. Just select the photos you want to remove, and then tap the trash can icon or click Delete. On your PC, select the photos you want to remove from your shared photo stream, right-click, and then select delete. The photos will be automatically deleted from the stream on all your devices and the devices of anyone subscribed to the stream. Note that any photos that were previously saved or downloaded from the shared photo stream to another location, such as the Camera Roll, will not be deleted. Learn more about deleting photos from a shared photo stream.
5. Copies of Photo Stream photos you have saved to your Camera Roll on an iOS device or imported into events in your iPhoto or Aperture library, and photos you have copied into a folder on your PC that's not part of My Photo Stream, will not be deleted when you delete photos from Photo Stream.
The above information can be found . Now, *personally*, I suggest you upload your photos to Microsoft's SkyDrive, Dropbox, Google Drive or any other good cloud storage that's easier to manage.