When you send an email to multiple people, those people can see who else got that email. But if you don't want certain email addresses to be visible to others, this is how you do it in Outlook 2010 in secrecy.
Camera images usually contain additional description about camera settings and scene information of the the picture taken. By using EXIF, you can view this data online.
If any file can not be deleted, then you can use the program LockHunter, which removes the active connections of other applications to that file, which allow you to change or delete file.