Image _Image = Image.FromFile("C:\\test.jpg");
ImageFormat iF = _Image.RawFormat;
MessageBox.Show(iF.ToString());

        
public static ImageFormat GetImageFormat(Image image)
{
   PropertyInfo[] propertyInfos = typeof(ImageFormat).GetProperties(BindingFlags.Public | BindingFlags.Static);

   // Have to check via Equals otherwise it cannot be compared
   foreach (PropertyInfo info in propertyInfos)
      if (info.GetValue(null, null).Equals(image.RawFormat))
         return (ImageFormat)info.GetValue(null, null);

   // Return MemoryBmp as default
   return ImageFormat.MemoryBmp;
}

public override string ToString()
{
   if (this == memoryBMP)
   {
      return "MemoryBMP";
   }
   if (this == bmp)
   {
      return "Bmp";
   }
   if (this == emf)
   {
      return "Emf";
   }
   if (this == wmf)
   {
      return "Wmf";
   }
   if (this == gif)
   {
      return "Gif";
   }
   if (this == jpeg)
   {
      return "Jpeg";
   }
   if (this == png)
   {
      return "Png";
   }
   if (this == tiff)
   {
      return "Tiff";
   }
   if (this == exif)
   {
      return "Exif";
   }
   if (this == icon)
   {
      return "Icon";
   }
   return ("[ImageFormat: " + this.guid + "]");
}

Bitmap bitmap = new Bitmap(@"C:\temp\test.jpg");

ImageFormat imageFormat = new ImageFormat(bitmap.RawFormat.Guid);

Console.WriteLine(imageFormat);

Console.WriteLine("Guid the same: " + (imageFormat.Guid == ImageFormat.Jpeg.Guid));

Console.WriteLine("Image types the same: " + (bitmap.RawFormat == ImageFormat.Jpeg));

Console.WriteLine("Image types really not the same?: " + bitmap.RawFormat.Equals(ImageFormat.Jpeg));

Console.WriteLine(ImageFormat.Jpeg.Guid + " | " + ImageFormat.Jpeg);

Console.ReadKey();