krummler

// Create an asset
let set = UIImageAsset()

// Define traits to be specific for the images
let darkTraits = UITraitCollection(traitsFrom: [UITraitCollection(userInterfaceStyle: .dark),
                                                UITraitCollection(displayScale: someDarkImage.scale)])
let lightTraits = UITraitCollection(traitsFrom: [UITraitCollection(userInterfaceStyle: .light),
                                                 UITraitCollection(displayScale: someLightImage.scale)])

// Register the images alongside the traits

krummler

combinedImages.imageAsset?.image(with: UITraitCollection(userInterfaceStyle: .light))
combinedImages.imageAsset?.image(with: UITraitCollection(userInterfaceStyle: .dark))

krummler

import UIKit

// MARK: Image helpers

extension UIImage {
    struct Constants {
        static let defaultTraits = [UITraitCollection(userInterfaceStyle: .dark),
                                    UITraitCollection(userInterfaceStyle: .light)]
    }