Port of accepted answer to http://stackoverflow.com/questions/10563986/uiimage-with-rounded-corners to Swift.

RoundCorners.swift

// get your image
var image = UIImage(named: "image.jpg")
// begin a new image
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, UIScreen.mainScreen().scale)
// add a clip in the shape of a rounded rectangle
UIBezierPath(roundedRect: imageView.bounds, cornerRadius: 10.0).addClip()
// draw the image in the view
image.drawInRect(imageView.bounds)
// set the image
imageView.image = UIGraphicsGetImageFromCurrentImageContext()
// clean up
UIGraphicsEndImageContext()

//This makes an ImageView rounded....
imageView.layer.cornerRadius = imageView.frame.size.width / 2
imageView.clipsToBounds = true