You can download Google Screensaver with or without installing the Google Pack.
What follows is a short guide to download and install the Google Pack Screensaver without downloading any of the other software in Google Pack or the even the Google Updater software. The Google screensaver will be installed without the Google Logo.
The Google Screensaver is probably the best piece of software in the entire Google Pack. The screensaver displays a slideshow of your digital pictures full screen or as a collage. The collage effect gives an impression as if someone is dumping Polaroid images on your desktop over time. Google screensaver works even on dual monitor screens.
Though the screensaver installer is only a few kilobytes, you need to download the entire Google updater application from pack.google.com to install the Google Screensaver.
If that is too much work for you, here is a quick tip to download a standalong google screensaver and as a bonus, this modified screensaver doesn't display the Google logo on the top right corner.
Download this standalone Google Screensaver scr here and save the file to your Windows folder (generally, C:\Windows in XP and C:\WinNT in Windows 2000).
The Google screensaver is now installed on your computer. To configure your screensaver and set it as the default screensaver on your system, follow these steps:
1. Right-click on your desktop and select "Properties" from the menu that appears
2. Select the "Screen Saver" tab from the "Display Properties" dialog
3. From the "Screen saver" drop-down, select "Google Pack Screensaver" then click the "Settings" button
4. From the settings window, you can select the transition, timing, and selection of photos in your screensaver.
Picasa screensaver also lets you display a slideshow of your photos when your computer is idle but that requires you to download the ~4MB picasa installer from Google.
Google Photos Screensaver