Extending the tool in bug 6653, add the ability to rebuild an image with changes incorporated into it. We know what recipes are being worked on by the user, and we may have a default configured for which image the user is working with, but the image may not already specify to include the packages produced by it, so that will need to be taken care of (we would assume all packages produced by the recipe(s) would be included).

(This is important both for machines where the image on it can only practically be updated as a complete image, e.g. a device with no networking capability; it is also useful when you need an updated image to run under emulation.)