I'm having an issue where I go in and select a desktop wall paper, and I have it set to change pictures every day from a small group of images, and everyday when I turn on my MBP, I end up with ugly Pink Screen not only on the page where I pick a user, but there it is again on my desktop. This seems like a bug to me. I just checked my System Preferences: Desktop and Screensaver, and the pictures are there with the change daily checkbox checked. I'm thinking this is a bug.
Now the system allows me to pick a folder on my computer to display as desktop backgrounds. I wonder if I would have been luck if I moved them to the desktop pictures folder?