Even though there are 512x512 pixel icon representations for all Apple apps, the Dock stays at 128 pixels maximum when using the Sie slider in the Dock's System Preferences panel. This old hint explains how to set the magnification level to up to 512 pixels (using the largesize key; defaults write com.apple.dock largesize -int 512).
Here's how to change the tile size (the maximum non-magnified dock icon size) to go along with the supersized zoomed icons. In Terminal, enter this command:
[robg adds: The easy way to return things to normal is to just use the Dock's System Preferences panel -- change the sliders, and the max values will return to their default settings. This works in every version of OS X from 10.2 onwards, I believe.]
Here's how to change the tile size (the maximum non-magnified dock icon size) to go along with the supersized zoomed icons. In Terminal, enter this command:
defaults write com.apple.dock tilesize -int 256; killall Dock
The tile size may be up to 256 pixels, so don't go any higher than that. Note that icons above 128 pixels are scaled, and you can notice some pixelation.
[robg adds: The easy way to return things to normal is to just use the Dock's System Preferences panel -- change the sliders, and the max values will return to their default settings. This works in every version of OS X from 10.2 onwards, I believe.]
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