LaunchScreen is black when i use image set

Anybody can help me with the problems of splashboard?

My request is to create a launchScreen.storyboard that can follows system's theme. So in the storyboard i use the image set resource which is created in Assets.xcassets. But i encountered the following problems:

  1. when i use image set resource,the splashboard is black, seems like springboard fail to generate the ktx file. But when i move the same image file to the root of Resource directory, it works. Why????

  2. Some image works when it is put in Image set, some file can't. But all file don't work when the image set contains both light image and dark image. Why???

  3. Suddenly it works for when i change compression attribute to lossess,so i guess the problems hanppened when my image is compressed. And two days later, the splash board is dark again when i debug. So what is the cache strategy for the splash board and the image resource used. How can i clear the cache, delete the app is not enough? Should i restart my phone?

That's all, anybody can help me?

LaunchScreen is black when i use image set
 
 
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