*Note: I am a Korean, so please understand if my English is not perfect.

Describe the bug
When configuring the picker to open only video files and presenting it, a crash or unexpected behavior occurs. It seems to be caused by UI-related code being executed on a background thread.

config.screens = [.library]
config.library.mediaType = .video

config.hidesBottomBar = false
config.onlySquareImagesFromCamera = false
config.library.isSquareByDefault = false

// Enable video trimming
config.showsVideoTrimmer = true

// No limit for selecting video duration
config.video.libraryTimeLimit = .infinity

// Maximum trimming duration: 60 seconds
config.video.trimmerMaxDuration = 60

// Send original file for server-side encoding
config.video.compression = AVAssetExportPresetPassthrough

To Reproduce
Steps to reproduce the behavior:

1. Configure the picker with mediaType = .video
2. Present the picker.
3. Select a video and try to enter the preview/trimming screen.
4. The error occurs when the preview is being fetched.

Expected behavior
setVideo and preview generation should run safely on the main thread, as it accesses UI-related APIs.

Screenshots
none

Environment (please complete the following information):

• Device: iPhone16Pro
• OS: iOS 26.0.1
• Xcode Version: 26.0.1
• Swift Version: 6.0

Installation Type

• SPM

Possible Cause
I suspect that the following property is accessed off the main thread. Since it touches UIApplication / UIWindowScene / UIScreen, it must be executed on the main thread.

YPImagePickerConfiguration.swift (line 22):

public static var screenWidth: CGFloat {
    var screenWidth: CGFloat = 0
    let windowScene = UIApplication.safeFirstWindowScene
    screenWidth = windowScene?.screen.bounds.width ?? 1.0
    if UIDevice.current.userInterfaceIdiom == .pad && YPImagePickerConfiguration.widthOniPad > 0 {
        screenWidth = YPImagePickerConfiguration.widthOniPad
    }
    return screenWidth
}

This seems to be triggered by the following line inside
setVideo in YPAssetZoomableView.swift, which is called via
mediaManager.imageManager?.fetchPreviewFor(video:):

let screenWidth = YPImagePickerConfiguration.screenWidth

Although changeAsset() is initially called on the main thread, it dispatches the logic to a background queue:

DispatchQueue.global(qos: .userInitiated).async {
    switch asset.mediaType {
    case .image:
        self.v.assetZoomableView.setImage(...)
    case .video:
        self.v.assetZoomableView.setVideo(...)
    ...
}

As a result, self.v.assetZoomableView.setVideo(...) is executed from a background thread. Since this leads to a call to YPImagePickerConfiguration.screenWidth, UIKit APIs are accessed off the main thread, which likely causes the crash or unexpected behavior.

Thanks!