This is probably the most complete collection of Cisco IOS you find on the internet. I have been digging through many servers. The biggest amount was actually found as link on archive.org to a lone little server. Many images present but downloading was a pain. The rest did sum up by strolling through ftp servers of universities all over the world.

Again a BIG torrent. As usual with more than standard recovery data to fix broken archives.

I have split the archive into series. So 1xxx stands for all routers and switches with a model number in the range of 1000 to 1999.

There are also a few other images like for ASA (firewall), SOHO and VOIP systems.

So you are able just to download a specific archive if you need it. To download everything and seed is of course way better ;)

I also added Packet Tracer 7.2. You can either register at netacad.com to use Packet tracer or run it anonymously. Cancelling the login is the way to do so if I recall right.

So if you are prepping Cisco certificates with GNS3 or want to modify the IOS on your hardware; this should help you a great deal.

I am not sure what the latest state is. A big amount of the collection was dated to 2011 but the other images I found may be more recent.

Enjoy :)