How to use iCloud.com to delete and recover pictures and videos from iCloud Photo Library
The great thing about all your pictures and videos being online is that sometimes all your pictures and videos are online...
iCloud Photo Library, currently in beta, makes sure all the pictures and videos of all the people and places you love, and all the memories you want to keep safe are backed up and available on all your devices, iPhone, iPad, and — and soon, on the Mac. If you've got stuff you simply don't like, or personal pictures and videos that you don't want to keep and don't want available, you can delete them. That way, neither you nor anyone else is at risk of ever seeing them again.
Full story from the iMore Blog...