Android 4.0.4 factory Images for Nexus Devices soju and yakju

Google just released factory image files for Nexus devices. These images will wipe data on your device and restore to original factory state

Factory Image "soju" for Nexus S (worldwide version) 

Factory Images "yakju" for Galaxy Nexus "maguro" (GSM/HSPA+)

Source http://code.google.com/android/nexus/images.html