Mountain Lion reverts back

I see that WW will download the image to the right folder in my home directory, then it will set the desktop to that image — but as soon as the image is set on the desktop, the physical file disappears and the desktop reverts back. If I quickly drag-and-drop the downloaded image file elsewhere before its deleted, I can continue to use it. But clearly, this product needs an update.

flumignan about Wallpaper Wizard: HD Wallpapers Collection