I believe the Cordova Camera API will let you take a picture which will add it to the Camera roll. It can also be used to get the file path for a picture in the camera roll. And the File plugin will let you rename files. So, in theory, this should be do-able.
On iOS you may have to workaround a bit: http://ootips.org/yonat/how-to-set-the-image-name-when-saving-to-the-camera-roll/