First of all, prepare several (any number) of good quality photo in high resolution. Create a new folder and put all images.
Now right-click the mouse on the desktop and select the menu item "Personalization".
In the dialog that appears, select "screen Saver".
Select the menu item "Photos" in the list of preset screen savers.
Click "Settings" and then click "Browse" and find the computer previously prepared folder.
Select the slide show speed and if necessary turn on the option of mixing photos.
Click save, set the time interval after which will turn on the screensaver and click "OK".