There are at least four bands that are named Cog. One from Australia, one from the Philippines, one from Croatia, and one from the USA.
These are photos from concerts where Cog played, so they may be of other bands that played the concert as well.
Cog Oct 20, 2006 Brisbane, Queensland, Australia Uploaded by Aphex Bob
Big Day Out 2006 Feb 3, 2006 Wayville, South Australia, Australia Uploaded by Stan Stan Stan
Big Day Out 2006 Jan 29, 2006 Melbourne, Victoria, Australia Uploaded by Womblingalong