We unfortunately didn't keep official copies of all the older Debian CD/DVD releases. We're still missing some, but here are some user-provided older images that have been supplied to us. Thanks to all those who have helped here, including:
There are MD5 checksums here to validate downloads, but there are no signatures. We don't believe (and don't want to suggest!) that these images have been tampered with since they were originally released by Debian, but we cannot be 100% sure.
Steve McIntyre <email@example.com>, on behalf of the Debian CD team.