OS X :: Looking For Wallpaper Folder?

Not that long ago, I found the folder that contains all the wallpaper backgrounds - I think it was somewhere in the Library? Anyways, after I found it, I added some of my own wallpaper images to the folder, so that they showed up in the pre-set folders of Nature, Plants, Abstract, etc, and not in my New Desktop Wallpapers folder. Well, now I have some new backgrounds I want to add, and for the life of me I can't remember where I found that folder before! I looked in the Library and the closest thing there is the Screensavers folder, but no wallpapers. Anyone know where this is located??