Forum:Changing the logo top left

How do you change the logo on the top left of a wikia? I haven't been able to find it in the help section. I know it was the subject of one of the first questions on this forum. Have old answers been archived somewhere Dr Joe Kiff 19:42, 12 November 2007 (UTC)
 * For Quartz upload Wiki wide.png
 * For MonoBook upload Wiki.png

Cheers! --Charitwo