Mac OS X Leopard Power Users' Clinic: Giant Icons
From
Mac OS X Leopard: The Missing Manual
In Mac OS X 10.5, Apple did something secret and artistic: It quadrupled the potential size of its icons. Instead of the measly 128 pixels square (which is all that most people ever see, maximum), you can blow them up to a colossal 512 pixels square. They're less like icons than art you can hang on your wall. To see the effect, you have to use Terminal.
Type this command, exactly as you see it here, but all on one line:
defaults write com.apple.finder DesktopViewOptions -dict IconSize -integer 256; killall Finder
It's quite a shocking sight--and, in fact, rather too big to be useful. It also works only on desktop icons--not icons in folders.
To turn the effect off, press c-J to open the View Options dialog box. Adjust the icon-size slider; the least touch of that slider turns the giganto-icon effect off again.
