1、使用SDWebImage

btn.sd_setImage(with: URL(fileURLWithPath: imagePath), for: .normal, completed: nil)

2、使用Kingfisher

btn.kf.setImage(with: URL(fileURLWithPath: imagePath), for: .normal, placeholder: nil, options: [.preloadAllAnimationData], progressBlock: nil) { (result) in

        }