获取启动图片的方法
| iOS | Display | Image Name |
|---|---|---|
| iOS5,6 | 3.5inch | LaunchImage |
| iOS5,6 | 3.5inch Retina | LaunchImage@2x |
| iOS5,6 | 4.0inch Retina | LaunchImage-568h@2x |
| iOS7,8 | 3.5inch Retina | LaunchImage-700@2x |
| iOS7,8 | 4.0inch Retina | LaunchImage-700-568h@2x |
| iOS8 | 4.7inch Retina | LaunchImage-800-667h@2x |
| iOS8 | 5.5inch Retina Portrait | LaunchImage-800-Portrait-736h@3x |
| iOS8 | 5.5inch Retina Landscape | LaunchImage-800-Landscape-736h@3x |