C#

function ImageUpload(file) {
                 xhr = new XMLHttpRequest();
                 xhr.open('post', 'SaveImageService.asmx', true);
                 xhr.setRequestHeader('Content-Type', "multipart/form-Data");
                 xhr.setRequestHeader('X-File-Name', file.fileName);
                 xhr.setRequestHeader('X-File-Size', file.fileSize);
                 xhr.setRequestHeader('X-File-type', file.fileType);
                 xhr.send(file);
            };

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;


namespace ImageUpload
{
    /// <summary>
    /// Summary description for SaveImageService
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    [System.Web.Script.Services.ScriptService]
    public class SaveImageService : System.Web.Services.WebService
    {

        [WebMethod]
        public void SaveImage()
        {
            var httpRequest = HttpContext.Current.Request;
            foreach (string file in httpRequest.Files)
            {
                var postedFile = httpRequest.Files[file];
                var filePath = HttpContext.Current.Server.MapPath("~/Images/" + postedFile.FileName);
                postedFile.SaveAs(filePath);
            }
        }
    }
}