Add image to media library programmatically in Sitecore

You can use below technique to add media file to media library in Sitecore.

var options = new Sitecore.Resources.Media.MediaCreatorOptions
   {
       AlternateText = "",
       FileBased = false,
       IncludeExtensionInItemName = false,
       KeepExisting = false,
       Versioned = false,
       Destination = "/sitecore/media library/Images/Contacts/" + ImageName,
       Database = Sitecore.Configuration.Factory.GetDatabase("master")
   };

   var filename = Server.MapPath(Img.FileName);
   var creator = new MediaCreator();
   var mediaItem = creator.CreateFromStream(Img.PostedFile.InputStream, filename, options);