Running
without a restart.

Extract Images from Screensavers

The screensavers are in this directory: /System/Library/ScreenSavers. If you control-click on the Cosmos saver, you can examine the package contents. The images are in this package directory: /Contents/Resources/Images.

The images are standard jpegs, so you can copy them to Home/Pictures and use them as desktops. Forest, Beach, and Abstract also contain images.