The icon composer 2.2 in Xcode 4.3.3 supports the icns of 1024x1024. However, for icon composer 2.4, it doesn\'t support that any more. This is ironic, since Apple pushes for th
The latest version of Xcode obsoletes the need for this (I'm using Xcode 5.1). Just click on your Project in the top left of the file listing, then choose the General tab. There is a section for the Icon Assets, click the "Use Asset Catalog" and your project will be updated to automatically build the icons file for you.
Then just click the arrow next to the Asset Catalog and it'll open a screen which shows you each of the required icon sizes with spots for @1x and @2x densities.