UIButton image automatically resizes even with constraints

Question

I have a minor issue, which I am probably not able to get my head around. I have a uibutton added programmatically. To that button I am adding a UIImage. I am just adding basic constraints, but for some reason it tends to shrink to a smaller size while running on screen.

Following is the code I have for generating the button:

var shareButton: UIButton!

    func addShareButton() {
        shareButton = UIButton()
        shareButton.autoresizesSubviews = false
        shareButton.clipsToBounds = true
        shareButton.translatesAutoresizingMaskIntoConstraints = false
        shareButton.adjustsImageWhenHighlighted = false
        shareButton.setImage(UIImage(named: "wshare"), for: .normal)
        shareButton.addTarget(self, action: #selector(shareButtonPressed), for: .touchDown)
        shareButton.addTarget(self, action: #selector(shareButtonReleased), for: .touchUpInside)
        view.addSubview(shareButton)
    }

    func addConstraints() {
        NSLayoutConstraint.activate([
            // Share Button
            shareButton.widthAnchor.constraint(equalToConstant: 60),
            shareButton.heightAnchor.constraint(equalToConstant: 60),
            shareButton.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -15),
            shareButton.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -25),
            ])
    }

    override func updateViewConstraints() {
        addConstraints()
        super.updateViewConstraints()
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        addShareButton()
    }

And what it generates is this:

The bigger box is supposed to be the actual size which is 60x60, but it magically shrinks to 32x32.

Can you help me point the issue. I know I am missing something quite silly, But I am not able get my head around it.

Answer 1

Personally, I like to keep my objects separate. While UIButton has a setImage(:UIImage) method, I prefer to create a UIButton then add my own UIImageView to it then add my own UIImage. So, in hierachy

-- UIButton
    -- UIImageView
        -- UIImage

With this, you can specify the specific bounds and any other variables associated to UIImageView. I find this methodology to be incredibly more concrete, especially if you have to alter the UIImageView.