I actually wanted to Convert RTF into Image so after googling a lot I\'ve got a code that does it by Paint() Event of Picturebox1 and it works perfectly : <
Your code produces an empty image file because you are not drawing anything onto 'newBitmap'.
If you want to draw anything onto 'newBitmap' you need to create a Graphics object from it. As I do not know where 'DrawRtfText' comes from and how it works my guess would be:
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
//...
Bitmap newBitmap = new Bitmap(pictureBox1.Width, pictureBox1.Height);
Graphics g = Graphics.FromImage(newBitmap);
g.DrawRtfText(this.richTextBox1.Rtf, this.pictureBox1.ClientRectangle);
newBitmap.Save(@"d:\adv.jpg");
}