How can I print my screenshot as 850 by 1100? IOS, Swift 3

Question

I have a screenshot button set up so that i can capture the entire view controller (except my status bar an navigation bar) and input that image to the camera roll. The only problem is that if i try to print this image from my camera roll, it prints an image only 1/4 of the page size. The image is too small, and i need it to be 850 by 1100.

How exactly could you code my screenshot to print, instead of a save to camera roll - and to specifically print 850 by 1100.

This is what my screenshot looks like:

///////// screenshot save
@IBAction func buttonAction(_ sender: UIButton) {


    //partial screenshot function
    let top: CGFloat = 46
    let bottom: CGFloat = 0
    let size = CGSize(width: view.frame.size.width, height: view.frame.size.height - top - bottom)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    let context = UIGraphicsGetCurrentContext()!
    context.translateBy(x: 0, y: -top)
    view.layer.render(in: context)
    let snapshot = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    //Save photo to camera roll
    UIImageWriteToSavedPhotosAlbum(snapshot!, nil, nil, nil)

    //Flash screen when photo is saved
    let shutterView = UIView(frame: view.frame)
    shutterView.backgroundColor = UIColor.black
    view.addSubview(shutterView)
    UIView.animate(withDuration: 0.3, animations: {
        shutterView.alpha = 0
    }, completion: { (_) in
        shutterView.removeFromSuperview()
    })


}

Please help! i have no idea what I'm doing