imageData property of CNContact

After setting the imageData property of CNContact through the API, I can see in the address book that the contact's avatar has been set to the imageData image, But when my phone version is iOS 17.1.0, when this contact calls in and locks the screen, I can see that this image is displayed in full screen, But when my phone version is iOS 17.5.1, when this contact calls in, the screen is locked and the image can only be displayed on the avatar, with a blurred image in the background, After iOS 17, contacts can set their avatars and posters separately in their contact list. How can I set these two images through code, just like setting the imageData property of CNContact through API. I see that there is a parameter in the CNContact property called _fullscreenImageData, but there is no value inside, and I am unable to obtain data for this parameter. I don't know how to manipulate this data in order to achieve the effect of setting up posters in the iOS 17.5.1 system.