Recently leaked Windows 7 build 7068 comes with lots of new wallpapers & User Pics. If you want to enjoy them in other Windows versions, you can download them using following link:

Download Windows 7 Build 7068 Wallpapers

Download Windows 7 Build 7068 User Pics

Extract the downloaded zip files using WinRAR or 7-Zip and you'll get folders containing Wallpapers and User Pics.

To use User Pics, copy the BMP files present in "Userpictures" folder to following folder: