在我的案例中有两个问题解决了它:

似乎有1MB的图像大小限制;没有文档，但当我优化相同的图像从3MB到1MB以下，它工作。这是有意义的，因为操作系统希望启动屏幕尽可能轻。 操作系统确实积极缓存启动屏幕!为了看到我的启动屏幕变化，我必须每次重置模拟器:Device > Erase所有内容和设置

You have to make sure that the file name of your image has a format like .png or .jpg at the end otherwise it will not work. Also, before adding your image, you have to make sure that the image file is in your "Assets.xcassets" folder within your project. This can be done with a simple drag and drop. Also, make sure when you've added your image to your storyboard that the image name in the top left also matches the real image file name. I would try looking into Constraints too. Hope this helps. Good luck with your App.

此问题与资产相关。Xcassets修复它，你必须添加图像作为资源，但不是在Xcassets文件夹，然后应该工作得很好

在我的例子中，我可以通过取消对Launchscreen故事板中使用的所有图像视图的属性检查器中的“清除图形上下文”来修复它。

为了你的信息，我已经在资产中导入了图像。PNG格式的Xcassets。

在投入了大量的时间后，我得到了解决方案:-

Step 1:- Quit Xcode
Step 2:- Delete the app from device/simulator
Step 3:- Restart your device (if you are using simulator then you have to quit simulator)
Step 4:- Clear all derived data 
Step 5:- Clear Bin
Step 6:- Open Xcode and relaunch the app, it will work 

我有这个问题后，添加图像到项目和射击设备的问题解决了