How to get Image format in C#

I am sharing  the code to get image format  the ASP.Net C#.

public static ImageFormat GetImageFormat(string fileName)

{

       string extension = Path.GetExtension(fileName);

            if (string.IsNullOrEmpty(extension))

                throw new ArgumentException(string.Format("Unable to determine file extension for fileName: {0}", fileName));

            switch (extension.ToLower())

            {

                case @".bmp":

                    return ImageFormat.Bmp;

                case @".gif":

                    return ImageFormat.Gif;

                case @".ico":

                    return ImageFormat.Icon;

                case @".jpg":

                case @".jpeg":

                    return ImageFormat.Jpeg;

                case @".png":

                    return ImageFormat.Png;

                case @".tif":

                case @".tiff":

                    return ImageFormat.Tiff;

                case @".wmf":

                    return ImageFormat.Wmf;

                default:

                    throw new NotImplementedException();

            }

       

}