It was a great app, and I used it for many years, even before the MacOS supported desktop pics itself. But it is unnecesary in OS X, since OS X supports auto-desktop pictures already. In fact, I have pics of my family, and it crossfades from pic to pic every 5 seconds. However, the developer's site is still a great source of pics. I would still reccomend its use in anything prior to OS X, though.