Q: How can I delete pictures from my iCloud Photo Stream?
A: Unfortunately, you can’t delete individual photos from the Photo Stream—at least not yet. Reports suggest that this feature may be added in iOS 5.1. However, as is usually the case with Apple, no specific information is available on when iOS 5.1 will be released.
Right now the only way to remove photos that are already in your iCloud Photo Stream is to delete the photo stream entirely.
You can do this by going to iCloud.com, logging in with your Apple ID and password and then choosing your account preferences by clicking on your name in the top right corner of the screen. From the window that subsequently appears, choose the Advanced option, and an option should appear to reset your Photo Stream.
Before doing this, you will want to ensure that you have downloaded any photos from your Photo Stream that you wish to keep, either using iPhoto or Aperture on your Mac or the iCloud Control Panel on Windows. Note that this will only delete the photos that are stored in iCloud—photos on your iPhone, iPod touch, iPad or computer will remain until you toggle the Photo Stream option off and back on again on each of these devices.
Once you’ve done this, you can even re-populate the Photo Stream with older photos by uploading them using Aperture, iPhoto or the Windows iCloud Control Panel.
While this is the only way to currently delete photos that are already in your Photo Stream, another alternative you may want to keep in mind is making use of the fact that photos are only uploaded to the Photo Stream when you are on a Wi-Fi connection. Therefore, if you toggle Wi-Fi off or you’re simply away from a configured Wi-Fi access point, any photos you take will remain only in your local camera roll until you return to Wi-Fi coverage. So, if you have photos that you don’t want to add to your Photo Stream, you can simply delete these from the local camera roll before connecting to a Wi-Fi network.