See this document: iCloud: How to delete photos from Photo Stream
The reason i ask is that my understanding of this is that it should all sync 'live'. But, if i delete photos from 'My Photo Stream' on my laptop, it remains in 'My Photo Stream' on my Iphone.
Deleting the photos from Photo Stream will delete them from iCloud, if that photo is still in iCloud. The photos will only be in iCloud for a month. So if you delete an older photo from Photo Stream, the change may not be applied to other devices, since they will see no change in iCloud.
Also photos you already saved from the Photo Stream will not be deleted, if you delete a photo from Photo Stream.
I would prefer it if ''My Photo Stream' on my laptop was static so i have a backup of all photos taken. Is this possible?
Set the preferences on your Laptop to automatically download from the PhotoStream. Are you using iPhoto on your Laptop? All photos saved from the Photo Stream to monthly events by automatic download will stay in your iPhoto library, when you delete photos from the Photo stream on your devices.
