So my screen saver just cycles through your pictures and actually does smooth transitions. And hey, I also made it grab the desktop and use that as the first image to transition from, so it comes on smoothly too. And I wrote a couple little transition effects to start. I'm doing them in software in C so they're slow as hell at the moment (at 1920x1200 or higher). It would be kind of fun to do transitions with D3D but I don't really want to worry about my screensaver using the 3d hardware right in all cases that it can come on.
I was pleased to find that MS actually made it pretty nice and easy to make screensavers. Hey it's just an EXE that you rename to a ".SCR" and you can do whatever you want in there.
Anyhoo, I'll post it in a few days once I get a freaking settings dialog box and such done.