Resizing image for icons for iPad2 - swift

Simple code for resizing image i.e. for navbar (source link) for png image with native res: 722x1028

let imageView = UIImageView(frame: CGRectMake(0, 0, 0, 60))
imageView.image =  UIImage(named: "girl")
imageView.contentMode = UIViewContentMode.ScaleAspectFit
self.navigationItem.titleView = imageView

And I get on iPad2:
I can manually render desired image by changing code:

let imageView = UIImageView(frame: CGRectMake(0, 0, 0, 60))
imageView.image = imageWithImage(UIImage(named: "girl")!, scaledToSize: CGSizeMake(42,60))
self.navigationItem.titleView = imageView

func imageWithImage(image:UIImage, scaledToSize newSize:CGSize) -> UIImage{
            UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0);
            image.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
            let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            return newImage
        }

But this is rather expensive solution.

Is there native library or simple swift solution to make png image automatically resized with good quality?

If you have hardcoded size 42x60 points for all devices, the best solution would be to provide pre-rendered image in that size. This is friendly to the battery and allows tweaking the image in a high quality editor before adding to the app: Resizing from 1000 pixels to 60 pixels is a bit drastic and will lead to loss of detail.

If that's not possible (i.e. image is dynamically loaded from the internet etc.), I would start my research with CIImage and CIFilter(name: "CILanczosScaleTransform") which provides very good interpolation quality, possibly followed by CISharpenLuminance if the loss of detail is too high.