Following the recent OTA roll-out, Android 4.2.2 factory images are now available for the Nexus 4, Nexus 7 (Wifi-only and 3G), Nexus 10 and GSM Galaxy Nexus ("yakju" and "takju" variants). As always, the files contain a complete backup of the base Android firmware for these devices. That means they allow experienced users to restore their devices back to stock, vanilla Android 4.2.2 Jelly Bean, which might be of use if you've managed to screw something up by flashing a custom ROM or allowing a root app to run amok. They're also one of the options open to folks who've not yet taken the 4.2.2 update and want to set things up from scratch.
Grab 'em directly from Google's developer site at the link below.
Source: Google Developers