User Account pictures in Windows 7

You can find the default pictures of Windows 7
user Account in a hidden folder, path given below.
Also you can find Admin & guest account picture
here.
 The default Pictures are located in the hidden
C:\ProgramData\Microsoft\User Account
Pictures\Default Pictures folder.

 The default Standard and administrator
account picture is the hidden
C:\ProgramData\Microsoft\User Account
Pictures\user.bmp file.

 The default Guest account picture is the hidden
C:\ProgramData\Microsoft\User Account
Pictures\guest.bmp file.

If you wish to change these simply replace them
with another file up to 128 x 128 pixels in size to
prevent it from being automatically cropped to fit
the user picture display box.