In addition to adding compatibility with OS X 10.8 Mountain Lion, Apple has updated Aperture to version 3.3.2 with a smattering of improvements. The professional photo organizer now enables you to sort projects and albums in the Library Inspector by date (in addition to name and kind), and adds the capability for Auto White Balance to correct color using Skin Tone mode (even when Faces is disabled). The update also fixes an issue that affected performance when entering or exiting Full Screen mode. ($79.99 new in the Mac App Store, free update, 530 MB)
Removing Photos from iPhoto
Despite iPhoto's long history, many people continue to be confused about exactly what happens when you delete a photo. There are three possibilities.
If you delete a photo from an album, book, card, calendar, or saved slideshow, the photo is merely removed from that item and remains generally available in your iPhoto library.
If, however, you delete a photo while in Events or Photos view, that act moves the photo to iPhoto's Trash. It's still available, but...
If you then empty iPhoto's Trash, all photos in it will be deleted from the iPhoto library and from your hard disk.