These are files containing source code for the Debian operating system.
Once you have downloaded all the ISO images you want, you will typically need to write them to installation media.
The images described here are sized to be written to at a minimum, but may be written to larger media if needed.
There are files here (SHA1SUMS, SHA256SUMS, etc.) which contain checksums of the images. These checksum files are also signed - see SHA1SUMS.sign, SHA256SUMS.sign, etc. Once you've downloaded an image, you can check:
For more information about how to do these steps, read the verification guide.
For convenience for some users, this unofficial alternative build includes non-free firmware for extra support for some awkward hardware.
See the Debian CD FAQ for lots more information about Debian CDs and installation.
The images here were put together by the Debian CD team , using debian-cd and other software.