Ah, that tactic only works with PNGs (and other "normal" image formats). You can apply the icns files directly to applications, though, by copying the icns folder into the Contents/Resources folder of the app and renaming it to Planeshift.icns. In fact, I've made a
script that will apply all the default icons to game, updater, and setup apps (my updater and setup were blue gems, but they actually have their own icons
). Simply download, decompress, drop in your PS folder, and double-click (yea alliteration!).
Notes:
1. It must be in your main PS folder.
2. It will apply the default icons, so if you wanted to use the plain gem icon for one of the apps, you'll have to apply that manually.
3. It assumes you haven't tampered with the icns files in support/icons (moving, renaming, etc).
4. If you set the icons via the copy/paste method, these settings will override the change we just made. Simply control-click the application with the copy/pasted icon, select "Get Info," click on the icon (in the top left, where you pasted before), and click delete. The default icon (which we just set) should be displayed.
EDIT: link fixed