Make sure the used image is square,

CircularImageView.swift

import UIKit

@IBDesignable class CircularImageView: UIImageView {
    @IBInspectable var lineWidth: CGFloat = 2
    @IBInspectable var color: UIColor = UIColor.red
    
    
    override func layoutSubviews() {
        super.layoutSubviews()
       
        if let image = self.image{
            self.image = image.cropToCircleWithBorderColor(color: self.color, lineWidth: self.lineWidth)
        }
    }
}

extension UIImage{
    func cropToCircleWithBorderColor(color : UIColor, lineWidth  : CGFloat) -> UIImage{
        let imageRect = CGRect(origin: CGPoint.zero, size: self.size)
        
        UIGraphicsBeginImageContext(imageRect.size)
        
        if let context = UIGraphicsGetCurrentContext(){
            context.addEllipse(in: imageRect)
            context.clip()
            
            self.draw(at: CGPoint.zero)
            
            //            for adding the stroke
            context.addEllipse(in: imageRect)
            color.setStroke()
            context.setLineWidth(lineWidth)
            context.strokePath()
            
            
            let newImage  = UIGraphicsGetImageFromCurrentImageContext()
            return newImage!
        }
        
        return UIImage()
    }
}