The Installer will download the latest available image and install it on a bootable SD Card or USB Stick so that it than can be installed onto the Vero 4k.
Generally it is the same image that is loaded on the Vero 4k before shipping but surely if shipping is a few month ago it will be a newer version.
Currently October is the latest available image. Normally images will be made available 1-2 weeks after an Update has been released. So you could expect the December Images anytime next week.