is it possible steganography on jpg

This does not look like obvious-to-everyone gibberish to down-vote without explanation :-)
Even if I voted 2 here I would try to explain why.
--SA

thanks SAKryukov here is the code i have used
i have tried it on jpeg but it also fails

dlg.Filter = "jpeg (*.JPEG)|*.JPEG|Bitmaps (*.bmp)|*.bmp|Tagged Image File Format(*.tif)|*.tif|PNG-24(*.png)|*.png";
if( dlg.ShowDialog() == DialogResult.OK )

System.Drawing.Imaging.ImageFormat format = System.Drawing.Imaging.ImageFormat.Jpeg;

img.Save(dlg.FileName, format);



using System;
using System.Drawing;
using System.Windows.Forms;
using System.Text;
using System.IO;

namespace PictureKey {

public class CryptUtility {

///

Hides a message in a bitmap

/// <param name="messageStream">The message to hide</param>
/// <param name="bitmap">The carrier bitmap</param>
/// <param name="keyStream">The key to use</param>
public static void HideMessageInBitmap(Stream messageStream, Bitmap bitmap, Stream keyStream, bool useGrayscale){
HideOrExtract(ref messageStream, bitmap, keyStream, false, useGrayscale);
messageStream = null;
}

///

Extracts an hidden message from a bitmap

/// <param name="bitmap">The carrier bitmap</param>
/// <param name="keyStream">The key used for hiding the message</param>
/// <param name="messageStream">Empty stream to receive the message</param>
public static void ExtractMessageFromBitmap(Bitmap bitmap, Stream keyStream, ref Stream messageStream){
HideOrExtract(ref messageStream, bitmap, keyStream, true, false);
}

///

Stepts through the pixels of a bitmap using a key pattern and hides or extracts a message

/// <param name="messageStream">If exctract is false, the message to hide - otherwise an empty stream to receive the extracted message</param>
/// <param name="bitmap">The carrier bitmap</param>
/// <param name="keyStream">The key specifying the unchanged pixels between two hidden bytes</param>
/// <param name="extract">Extract a hidden message (true), or hide a message in a clean carrier bitmap (false)</param>
private static void HideOrExtract(ref Stream messageStream, Bitmap bitmap, Stream keyStream, bool extract, bool useGrayscale){
//Current count of pixels between two hidden message-bytes
//Changes with every hidden byte according to the key
int currentStepWidth = 0;
//Current byte in the key stream - normal direction
byte currentKeyByte;
//Current byte in the key stream - reverse direction
byte currentReverseKeyByte;
//current position in the key stream
long keyPosition;

//maximum X and Y position
int bitmapWidth = bitmap.Width-1;
int bitmapHeight = bitmap.Height-1;

//Color component to hide the next byte in (0-R, 1-G, 2-B)
//Rotates with every hidden byte
int currentColorComponent = 0;

//Stores the color of a pixel
Color pixelColor;

//Length of the message
Int32 messageLength;

if(extract){
//Read the length of the hidden message from the first pixel
pixelColor = bitmap.GetPixel(0,0);
messageLength = (pixelColor.R << 2) + (pixelColor.G << 1) + pixelColor.B;
messageStream = new MemoryStream(messageLength);
}else{

messageLength = (Int32)messageStream.Length;

if(messageStream.Length >= 16777215){ //The message is too long
String exceptionMessage = "Themessage is too long, only 16777215 bytes are allowed.";
throw new Exception(exceptionMessage);
}

//Check size of the carrier image

//Pixels available
long countPixels = (bitmapWidth*bitmapHeight) -1;
//Pixels required - start with one pixel for length of message
long countRequiredPixels = 1;
//add up the gaps between used pixels (sum up all the bytes of the key)
while((keyStream.Position < keyStream.Length)&&(keyStream.Position < messageLength)){

countRequiredPixels += keyStream.ReadByte();

}