Change the default user profile picture in Windows 7

The following will get you to where every user by default has a custom profile picture.

1. You first need to go to C:\ProgramData\Microsoft\User Account Pictures and rename user.bmp to user_old.bmp.
2. Now copy your custom picture to that directory. Make sure that it's a bmp, and it's called user. You also need to make sure that it's 128x128 pixels.
3. Reboot the computer and the new picture will now be the default profile picture.

Here is the default profile picture that I use in my Windows 7 deployments.

Enjoy