https://twitter.com/S_Shimotori_pub/status/1143483831745302528

ViewController.swift

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // static images
        let lightImage = UIImage(named: "LightImage")!
        let darkImage = UIImage(named: "DarkImage")!

        // https://developer.apple.com/documentation/uikit/uitraitcollection/1651062-init
        let lightCollection = UITraitCollection(userInterfaceStyle: .light)
        let darkCollection = UITraitCollection(userInterfaceStyle: .dark)

        let imageAsset = UIImageAsset()
        // https://developer.apple.com/documentation/uikit/uiimageasset/1624974-register
        imageAsset.register(lightImage, with: lightCollection)
        imageAsset.register(darkImage, with: darkCollection)

        let imageView = UIImageView()
        // dynamic image
        // https://developer.apple.com/documentation/uikit/uiimageasset/1624976-image
        imageView.image = imageAsset.image(with: UITraitCollection.current)
        imageView.frame = CGRect.init(x: 0, y: 0, width: 400, height: 400)
        view.addSubview(imageView)
    }

}

ViewController1.swift

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // static images
        let image0 = UIImage(named: "Image0")!
        let image1 = UIImage(named: "Image1")!

        let lightCollection = UITraitCollection(userInterfaceStyle: .light)
        let darkCollection = UITraitCollection(userInterfaceStyle: .dark)

        // You can also use `traitCollection` from `UITraitEnvironment`.
        let imageAsset0 = UIImageAsset()
        imageAsset0.register(image0, with: lightCollection)
        imageAsset0.register(image1, with: darkCollection)
        let dynamicImage0 = imageAsset0.image(with: self.traitCollection)
        let imageAsset1 = UIImageAsset()
        imageAsset1.register(image1, with: lightCollection)
        imageAsset1.register(image0, with: darkCollection)
        let dynamicImage1 = imageAsset1.image(with: self.traitCollection)

        let button = UIButton()
        button.frame = CGRect(x: 0, y: 300, width: 400, height: 400)
        button.setBackgroundImage(dynamicImage0, for: .normal)
        button.setBackgroundImage(dynamicImage1, for: .highlighted)
        button.addTarget(self, action: #selector(tapped(_:)), for: .touchUpInside)
        view.addSubview(button)
    }

    @objc private func tapped(_ sender: UIButton) {
        switch overrideUserInterfaceStyle {
        case .dark:
            overrideUserInterfaceStyle = .light
        default:
            overrideUserInterfaceStyle = .dark
        }
    }

}