Xamarin.iOS util to measure/detect iPhone 5 screen and pull the right image from the bundle.

ScreenResolutionUtil.cs

using System;
using System.IO;

using MonoTouch.UIKit;

namespace 
{
  public static class ScreenResolutionUtil
	{
		public static bool IsTall
		{
			get {
				return UIDevice.CurrentDevice.UserInterfaceIdiom
					== UIUserInterfaceIdiom.Phone
						&& UIScreen.MainScreen.Bounds.Size.Height
						* UIScreen.MainScreen.Scale >= 1136;
			}
		}

		public static int ScreenHeight
		{
			get {
				return (IsTall) ? 568 : 480;
			}

		}
		
		private static string tallMagic = "-568h@2x";
		public static UIImage FromBundle16x9(string path)
		{
			//adopt the -568h@2x naming convention
			if(IsTall)
			{
				var imagePath = Path.GetDirectoryName(path.ToString());
				var imageFile = Path.GetFileNameWithoutExtension(path.ToString());
				var imageExt = Path.GetExtension(path.ToString());
				imageFile = imageFile + tallMagic + imageExt;
				return UIImage.FromBundle(Path.Combine(imagePath,imageFile));
			}
			else
			{
				return UIImage.FromBundle(path.ToString());
			}
		}
	}
}