You don't have to 'download' them. Just use an image extractor to get them out of the mpq files.
I'll attach one to this post so you can download it.
All you have to do is run the program, then select the mpq file to open (either war3.mpq for Reign of Chaos icons or war3x.mpq for Frozen Throne icons; both located in your Warcraft 3 directory).
Then search, with the program, until you find the icon you're looking for.
Finally finding about some of the bots that are flooding the users online - bytespider apparently is a huge offender here - ignores robots.txt and comes in from a ton of different IPs
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.