The only way, that I know, to remove a photo from photostream is to turn it off in iCloud, but than you lose all the photos in photostream.You have to delete the original photos from out of the camera roll on the device that took the picture or the screen shot. It is kind of a pain bit hopefully on future updates they will work on it. Also to delete all photo stream photos you can go to settings then iCloud then photostream and turn off. It will ask you if you want to remove all photos.
It works on both platforms.I've never really taken the time to look into how the photo stream works Through iCloud. Does this work on any pc or does it have to be a Mac?
Just bumping this up, as I have the same problem. I have not tried but when Photostream is sent to my Mac, will I be able to use/delete/edit them or will they just stay stale in a photostream album?I disabled Photostream shortly after 5.0 was released due to the lack of user controls and inability to delete individual photos from the stream. I got tired of jumping through hoops and being forced to delete my entire stream just to remove one image. I'll reenable it when they add the ability to delete individual images.