Xcode 6资产目录自动创建较小比例的图像

With the need of 3x images in iOS 8 I figured it would be easier to manage images with an asset catalog in Xcode 6. I am trying to just provide a single image, the 3x scaled image to the asset catalog and I want Xcode to automatically downscale that image to generate 2x and 1x versions of the 3x image, so that I don't have to do it manually.With the need of 3x images in iOS 8 I figured i