problem in picture display

you are only seeing the second image because you are using the UI thread to do the showing of the image.  You see, the UI thread will not update the form until ALL of the code has been completed.

you can get around this by using a Timer control.  Put the timer control on the form, set it's interval to 5000, and set Enabled = FALSE.  now in your current code, instead of doing a "Thread.Sleep(5000);"(also remove the other thread code), enable the timer.  Double click on the timer to create the "Tick" event.  In the Tick event, copy your code to display the second image.

your code would like something like this...

private void Form1_Load(object sender, EventArgs e)
{
       pbThumbImage.Image = new Bitmap(new MemoryStream(objEmployee.Picture));
       timer.Enabled = true;
}

private void timer_Tick(object sender, EventArgs e)
{
       timer.Enabled = false;
       pbThumbImage.Image = global::TimeEntrySystem.Properties.Resources.DefaultImage;
}