High quality JPEG compression with c#

I am using C# and want to save images using JPEG format. However .NET reduces quality of the images and saves them with compression that is not enough.

I want to save files with their original quality and size. I am using the following code but compression and quality are not like the original ones.

Bitmap bm = (Bitmap)Image.FromFile(FilePath); 
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders(); 
ImageCodecInfo ici = null; 

foreach (ImageCodecInfo codec in codecs)
{ 
    if (codec.MimeType == "image/jpeg") 
    ici = codec; 
} 

EncoderParameters ep = new EncoderParameters(); 
ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)100); 
bm.Save("C:\\quality" + x.ToString() + ".jpg", ici, ep);

I am archiving studio photos and quality and compression is very important. Thanks.