Use the Create menu in Picasa to make a screen saver that does not enable Picasa to be displayed on your computer. You should first install Picasa on the computer where you want to display the screen saver.
1. Select the picture of the Picasa you want to display in the slide show.
2. At the top of the Picasa menu, go to create > Screen saver.
3. In the Open Display Properties dialog box, click OK to create a copy of all the selected pictures and save them to a new folder under my Pictures/screen saver on your computer.
To rearrange or delete a picture in a slide show:
1. Enter the "folder on disk" picture set in Picasa.
2. Look for a folder called Screen saver.
3. Drag and drop pictures to rearrange their display order. To delete a picture, select the picture, and then click the Delete key on the keyboard. Files copied on the computer (not the original file) will be deleted.