ScrollView contentSize Larger than Bounds, Yet No Scrolling - ios

Question

I have a scrollView containing a single image. The image's bounds are greater than the scrollView's frame. I have set the scrollView's contentSize to be equal to the image's bounds.
Yet no scrolling. I have no idea what could be causing this.
override func viewDidLoad() {
super.viewDidLoad()
var matches = SortThread.getSortThread().retrieveMatches()
scrollView.frame = CGRectMake(0, navigationController!.navigationBar.frame.height - 20, UIScreen.mainScreen().bounds.width, view.bounds.height - (navigationController!.navigationBar.frame.height - 20))
var imageName = String()
imageName = matches[0].pictures![0]
var parsedImageName = imageName.componentsSeparatedByString(".") as [String]
var newImageName: String = parsedImageName[0] as String
let path = NSBundle.mainBundle().pathForResource("MVLMP Images (Resized)/" + newImageName, ofType: "jpg")
var image = UIImage()
image = UIImage(contentsOfFile: path!)!
var imageView = UIImageView(image: image)
var ratio: CGFloat = image.size.width/image.size.height
var screenHeight: CGFloat = UIScreen.mainScreen().bounds.height - navigationController!.navigationBar.frame.height - 20
if(ratio > 1){
imageView.frame = CGRectMake(0, 0, ((scrollView.bounds.width)/7) * 6, 0)
imageView.frame = CGRectMake(0, 0, imageView.frame.width, imageView.frame.width * ratio)
} else {
imageView.frame = CGRectMake(0, 0, 0, (screenHeight/9)*8)
imageView.frame = CGRectMake(0, 0, imageView.frame.height * ratio, imageView.frame.height)
}
scrollView.addSubview(imageView)
scrollView.contentSize.width = imageView.frame.width
scrollView.contentSize.height = imageView.frame.height
}
}
I've printed out the scrollView.contentSize.width and the scrollView.bounds.width and the content width is in fact greater than the bounds width by about 40.

Answer 1

As Muc Dong commented, I was adding the width of the images to the scrollView's contentSize.width. This was not necessarily the correct thing to do as in my case there is some margin between the images that I was not accounting for. This margin should of been included in the additions to to scrollView.contentSize.width.