One of the benefits of owning a Nexus device is the openness and freedom to play around with the device and install custom images. Modders, tinkerers, and hackers owning a Nexus device can live a little more dangerously now that Google has released factory images containing Android 4.3 Jelly Bean for a number of Nexus devices.
An update to Nexus devices, particularly the T-Mobile Nexus 4, was earlier rolled out. The update, with a build number JWR66Y, was later reported to have also arrived for other devices such as the Nexus 10 and the 3G version of the 2012 Nexus 7. The new Nexus 7 also just received an update, this time with the number JSS15Q, that fixed, among other things, multitouch issues that have been plaguing owners of the tablet.
Both the JWR66Y and the JSS15Q builds are now available to the public as flashable factory images. These images are especially useful for restoring a device to its pristine state but with a more updated Android version. Not all Nexus devices are covered, however. Supported devices include the WiFi version of the 2013 Nexus 7, the Nexus 10, the Nexus 4, both WiFi and Mobile versions of the old Nexus 7, and GSM versions of the Galaxy Nexus.
Google also provides instructions on how to use the images to restore the devices to their factory state. The usual warnings and precautions related to flashing images also apply, especially for those who are attempting to do it for the first time.