post image base64 to server and save image to disk same fileUpload, that preview in browser

Change submit to call ajax instead:

<input type="submit" value="Send" onclick="SendData(); return false;" />

Add script to handle the sending:

<script type="text/javascript">    function SendData() {        var fd = new FormData();        fd.append('file', $('#imageInput')[0].files[0]);        $.ajax({            url: '/UploadImage.ashx',            data: fd,            processData: false,            contentType: false,            type: 'POST',            success: function (data) {                alert(data);            }        });    }</script>

Create .ashx handler that will handle the save:

public class UploadImage : IHttpHandler {  public void ProcessRequest(HttpContext context) {    var parser = new MultipartParser(context.Request.InputStream);    if (parser.Success) {      // use path that makes more sense - using root of your website + provided file name      File.WriteAllBytes(Path.Combine(context.Server.MapPath("~/"), parser.Filename), parser.FileContents);    }  }  public bool IsReusable {    get { return false; }  }}

MultipartParser is opensource class - see http://multipartparser.codeplex.com/SourceControl/latest#MultipartParser.cs

For convenience also attached:

public class MultipartParser {  public MultipartParser(Stream stream) {    this.Parse(stream, Encoding.UTF8);  }  public MultipartParser(Stream stream, Encoding encoding) {    this.Parse(stream, encoding);  }  private void Parse(Stream stream, Encoding encoding) {    this.Success = false;    // Read the stream into a byte array    byte[] data = ToByteArray(stream);    // Copy to a string for header parsing    string content = encoding.GetString(data);    // The first line should contain the delimiter    int delimiterEndIndex = content.IndexOf("\r\n");    if (delimiterEndIndex > -1) {      string delimiter = content.Substring(0, content.IndexOf("\r\n"));      // Look for Content-Type      Regex re = new Regex(@"(?<=Content\-Type:)(.*?)(?=\r\n\r\n)");      Match contentTypeMatch = re.Match(content);      // Look for filename      re = new Regex(@"(?<=filename\=\"")(.*?)(?=\"")");      Match filenameMatch = re.Match(content);      // Did we find the required values?      if (contentTypeMatch.Success && filenameMatch.Success) {        // Set properties        this.ContentType = contentTypeMatch.Value.Trim();        this.Filename = filenameMatch.Value.Trim();        // Get the start & end indexes of the file contents        int startIndex = contentTypeMatch.Index + contentTypeMatch.Length + "\r\n\r\n".Length;        byte[] delimiterBytes = encoding.GetBytes("\r\n" + delimiter);        int endIndex = IndexOf(data, delimiterBytes, startIndex);        int contentLength = endIndex - startIndex;        // Extract the file contents from the byte array        byte[] fileData = new byte[contentLength];        Buffer.BlockCopy(data, startIndex, fileData, 0, contentLength);        this.FileContents = fileData;        this.Success = true;      }    }  }  private int IndexOf(byte[] searchWithin, byte[] serachFor, int startIndex) {    int index = 0;    int startPos = Array.IndexOf(searchWithin, serachFor[0], startIndex);    if (startPos != -1) {      while ((startPos + index) < searchWithin.Length) {        if (searchWithin[startPos + index] == serachFor[index]) {          index++;          if (index == serachFor.Length) {            return startPos;          }        } else {          startPos = Array.IndexOf<byte>(searchWithin, serachFor[0], startPos + index);          if (startPos == -1) {            return -1;          }          index = 0;        }      }    }    return -1;  }  private byte[] ToByteArray(Stream stream) {    byte[] buffer = new byte[32768];    using (MemoryStream ms = new MemoryStream()) {      while (true) {        int read = stream.Read(buffer, 0, buffer.Length);        if (read <= 0)          return ms.ToArray();        ms.Write(buffer, 0, read);      }    }  }  public bool Success {    get;    private set;  }  public string ContentType {    get;    private set;  }  public string Filename {    get;    private set;  }  public byte[] FileContents {    get;    private set;  }}