PicPodz is on the Mac App Store (http://is.gd/iAEWHn)
PicPodz is an OS X 10.10 desktop photo slideshow in the form of a sphere. Just drag images into the window then change modes. Pics will change randomly. Resize or maximize to suit your needs.
I recommend organizing copies of pics into folders, rather than using originals. Just select all images and drop them into the window.