Basic check for identical images

Compare two images.cs

namespace Utils.Extension
{
  using System.Drawing;
	using System.Security.Cryptography;

	public static class ExtendImage
	{
		public static bool EqualImage(this Image img, Image imgToCompare)
		{
			if (img == null && imgToCompare == null)
				return true;
			if ((img == null && imgToCompare != null) || (img != null && imgToCompare == null))
				return false;
			if (img.Size != imgToCompare.Size)
			{
				return false;
			}
			else
			{
				//Convert each image to a byte array

				var ic = new ImageConverter();
				byte[] btImage1 = new byte[1];
				btImage1 = (byte[]) ic.ConvertTo(img, btImage1.GetType());
				byte[] btImage2 = new byte[1];
				btImage2 = (byte[]) ic.ConvertTo(imgToCompare, btImage2.GetType());

				//Compute a hash for each image

				var shaM = new SHA512CryptoServiceProvider();
				byte[] hash1 = shaM.ComputeHash(btImage1);
				byte[] hash2 = shaM.ComputeHash(btImage2);

				//Compare the hash values

				for (int i = 0; i < hash1.Length && i < hash2.Length; i++)
				{
					if (hash1[i] != hash2[i])
						return false;
				}

				return true;
			}
		}
	}
}