Somehow, I don't know how or when, I deleted preview.app. Everything else is fine. What's the easiest way to get it back?
- Copy it from a backup or another Mac.
Download an OS X installer from App Store, and use Pacifist to copy the application bundle.
Wait until 10.9 is released.
- Download an OS X installer from App Store and install it on a virtual machine with VMware Fusion, Parallels Desktop, or VirtualBox.
- Do an upgrade install of OS X from the recovery partition.