43 Mountain Lion hidden pictures
In the New Mac OS X there are 43 high resolution pictures hidden in a directory of the screensaver framework.
It seems (as said by OSX Daily, who discovered the images) that they come from National Geographic, the Hubble Space telescope, and some amazing photographers.
The resolution for the images is 3200×2000, so they should be fantastic if you show them on a retina display.
To use the images you should open the containing folder (shortcuts: Command + Shift + G) /System/Library/Frameworks/ScreenSaver.Framework/Versions/A/Resources/Default Collections/
you can also open the Terminal App and then type the following command:
# open /System/Library/Frameworks/ScreenSaver.Framework/Versions/A/Resources/Default Collections/
Now you can copy the images and use them as you want.