For some reason my desktop (G4 dual 500 mhz) will refuse to fade between pictures on the desktop (change picture every 5 sec.). Instead, it will just abubtly switch. I tried it out on my ibook, and it fades perfectly between pictures. Why is it that my ibook will fade background images while my desktop computer will not? Both comptuers are running OS X 10.2.1 (clean install). Is there something wrong with my desktop?