I tried this for a while, and you can get one that works pretty easily searching for screensaver osx on google. BUT, while it worked great on the normal computers the Retina displays would not display it, so i tried compiling on a MBPR instead and same thing. What I did finally get working was to dump pictures to a folder inside of /Library/Screen Savers/Default Collections. then set my screen saver to use that folder and shuffle the pictures.
Then used a login script to set the screensaver the first time for the users
#!/bin/perl -w
my $ss = $HOME . "/.screensaverset";
unless(-e $ss) {
syslog('notice', "Setting default ScreenSaver");
system("defaults -currentHost write com.apple.screensaver moduleDict -dict moduleName "iLifeSlideshows" path "/System/Library/Frameworks/ScreenSaver.framework/Resources/iLifeSlideshows.saver" type 0");
system("defaults -currentHost write com.apple.ScreenSaverPhotoChooser LastViewedPhotoPath """);
system("defaults -currentHost write com.apple.ScreenSaverPhotoChooser SelectedFolderPath "/Library/Screen Savers/Default Collections/MyPictures" ");
system("defaults -currentHost write com.apple.ScreenSaverPhotoChooser SelectedSource -int 3");
system("defaults -currentHost write com.apple.ScreenSaverPhotoChooser ShufflesPhotos -bool true");
system("touch "$ss"");
}
hope that helps, it took me months of fiddling with trying to compile a screensaver before God gave me this solution.
