C# — Get image size by name in Xamarin.Forms for iOS and Android platforms

ImageMeter.cs

//
//  ImageMeter.cs
//  Created by Alexey Kinev on 9 May 2015.
//
//      No Rights Reserved
//      http://creativecommons.org/publicdomain/zero/1.0/
//
// Get image size by name in Xamarin.Forms for iOS and Android platforms.
//
using System;
using Xamarin.Forms;

#if __IOS__
using UIKit;
#endif

#if __ANDROID__
using Android.App;
using Android.Graphics;
using Android.Content.Res;
#endif

namespace Project
{
	public static class ImageMeter
	{
		public static Size GetImageSize(string fileName)
		{
			#if __IOS__
			UIImage image = UIImage.FromFile(fileName);
			return new Size((double)image.Size.Width, (double)image.Size.Height);
			#endif

			#if __ANDROID__
			var options = new BitmapFactory.Options {
				InJustDecodeBounds = true
			};
			fileName = fileName.Replace('-', '_').Replace(".png", "");
			var resId = Forms.Context.Resources.GetIdentifier(
				fileName, "drawable", Forms.Context.PackageName);
			BitmapFactory.DecodeResource(
				Forms.Context.Resources, resId, options);
			return new Size((double)options.OutWidth, (double)options.OutHeight);
			#endif

			return Size.Zero;
		}
	}
}

Is this method placed in a PCL?, because when I implement it some classes are not resolved such as UIImage , BitmapFactory ?