LightZone, once discontinued, has been restored to life as an Open-Source project. It is still being developed and improved, but downloading the application requires creation of an account and logging-in to access the download.
You can read the project's rationale behind the download requirements, and can create an account--or log-in to your account--from the right side of the project's home page. When first creating an account, you'll have to open the e-mail sent from the project and click on the link to confirm your request. Once you're logged-in,
- You can now open an image via command line, OS context menu, or drag-and-drop on LightZone shortcut icon.
- On Mac OS X, full-screen mode is now supported on OS X 10.7 (Lion) or newer.
- On Mac OS X, HiDPI retina mode is now supported.
- You can now select multiple thumbnails with Ctrl-Shift-Click.
- OS X 10.7 or later