Apple expects all its iOS applications to have launch images for all supported devices and resolutions to enhance the user experience at application launch. In general, an iPhone application should have a Portrait launch image and an iPad application should have a launch image as per the launch orientation of the application. As mentioned here, every application must include launch image for different sizes and resolution. Looking at the sizes closely, we notice that Apple expects fullscreen launch images for iPhone whereas it expects non fullscreen launch images for iPad. This size recommendation by Apple is irrespective of the fact whether the application is meant to be fullscreen or not.
A launch image must be visible instantly when the user starts the application and must remain visible until the application is fully ready to use. For AIR applications, AIR Runtime needs to be initialized too and launch image must remain visible till this initialization is complete. To achieve this, AIR Runtime shows the same launch image as shown by iOS till the time application is fully ready to use. Recently, we faced some issues where launch images appeared to drift slightly during application launch. This occurred because of the above mentioned fact that Apple expected fullscreen launch images for iPhone and non fullscreen launch images for iPad. Drifts were observed due to image scaling when we tried to display the fullscreen launch image in non fullscreen area(on iPhone) or a non fullscreen launch image in fullscreen area(on iPad).
To overcome these issues permanently, we changed the guidelines for launch screen image sizes for iPad in AIR 3.4. We now expect all AIR applications meant for iOS platform to include only the fullscreen launch images as the resolution of the supported device. This means that expected image size of default portrait image for high resolution iPad would be 1536×2048 from AIR 3.4 onwards. This is irrespective of the fact that application is meant to be fullscreen or not. The extra 40 pixels are hidden behind the status bar for non fullscreen applications.
From AIR 3.4 onwards, the expected launch image sizes for AIR applications targeted for iOS platform are mentioned in the table below:-
Launch Image Size
|iPhone and iPod (3rd Generation)||
320 x 480
|iPhone4, iPhone 4S & iPod Touch (4th Generation)||
640 x 960
|iPhone 5 and iPod Touch (5th Generation)||
640 x 1136
|iPad 1 and iPad 2||
768 x 1024 (portrait)
1024 x 768 (landscape)
|iPad 3rd Generation||
1536 x 2048 (portrait)
2048 x 1536 (landscape)
For more details on naming conventions of launch images, please refer to article available here