UPDATE 10 Jun 2023: As of Debian 12 (Bookworm), firmware is included in the normal Debian installer images. USERS NO LONGER NEED TO LOOK FOR SPECIAL VERSIONS HERE.
For older releases (11.x/Bullseye and older), there are are some extra images in the archive directory. These are equivalent to the normal images we produced regularly except in that they also include non-free firmware to make things easier on some systems requiring proprietary but redistributable firmware. See http://wiki.debian.org/Firmware for more details.
There are three types of image here: