Замена UISwitch с кастомными картинками для состояний

CustomSwitch.swift

import UIKit

@IBDesignable class CustomSwitch: UIButton {
    var onValueChanged: ((Bool) -> Void)?
    
    @IBInspectable var isOn: Bool = false {
        didSet {
            isSelected = isOn
            onValueChanged?(isOn)
        }
    }
    
    @IBInspectable var onImage: UIImage? {
        didSet {
            setUp()
        }
    }
    
    @IBInspectable var offImage: UIImage? {
        didSet {
            setUp()
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setUp()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setUp()
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        setUp()
    }
    
    private func setUp() {
        clipsToBounds = true
        isSelected = false
        setImage(onImage, for: .selected)
        setImage(offImage, for: .normal)
        addTarget(self, action: #selector(invertIsOn), for: .touchDown)
    }
    
    func invertIsOn() {
        isOn = !isOn
    }
}

1. Делаем кнопку типа Custom.
2. Назначаем кнопке тип CustomSwitch.
3. Задаем картинки для состояний