How to merge multiple images into one with Xamarin.iOS C#

IImageMergeService.cs

namespace Mobile.Services
{
    public interface IImageMergeService
    {
        byte[] MergeTwoImageByteArrays(byte[] imageBackgroundBytes, byte[] imageForegroundBytes);
    }
}

ImageMergeService.cs

using System;
using System.Runtime.InteropServices;
using CoreGraphics;
using Foundation;
using UIKit;

namespace Mobile.Platforms.Ios.Services
{
    public class ImageMergeService : IImageMergeService
    {
        public byte[] MergeTwoImageByteArrays(byte[] imageBackgroundBytes, byte[] imageForegroundBytes)
        {
            byte[] resultByteArray;
            UIImage resultImage;

            var dataBackground = NSData.FromArray(imageBackgroundBytes);
            var imageBackground = UIImage.LoadFromData(dataBackground);

            var dataForeground = NSData.FromArray(imageForegroundBytes);
            var imageForeground = UIImage.LoadFromData(dataForeground);

            var width = imageBackground.Size.Width;
            var height = imageBackground.Size.Height;

            // Get max width and height of the image
            width = imageForeground.Size.Width > width ? imageForeground.Size.Width : width;
            height = imageForeground.Size.Height > height ? imageForeground.Size.Height : height;

            using (var renderer = new UIGraphicsImageRenderer(new CGSize(width, height)))
            {
                resultImage = renderer.CreateImage((UIGraphicsImageRendererContext ctxt) =>
                {
                    imageBackground.Draw(CGPoint.Empty);
                    imageForeground.Draw(CGPoint.Empty);
                });
            }
            
            using (NSData imageData = resultImage.AsPNG())
            {
                resultByteArray = new Byte[imageData.Length];
                Marshal.Copy(imageData.Bytes, resultByteArray, 0, Convert.ToInt32(imageData.Length));
            }

            return resultByteArray;
        }
    }
}