Just create a folder to contain all of the boot screens, and configure the program to access that folder. Then, each time you begin or end your Windows session, you'll get a new animated image.
The program is compatible with Service Packs 1 and 2. And you don't need to worry about unzipping any screens in zip format, since the program can recognize and access this format on its own.
The display of the screens can be randomized or you can choose to establish a set order.