Trouble with Graphics.drawstring

[DerekM]

Having some trouble, need help.
So, what I've got is a picturebox and a textbox, I got some code to put text into a picturebox so I could better understand how it works, but what I don't understand is how to put the text on top of the image that is in the picturebox, can anyone tell me how to do that?

Here's the code

Dim Graph As Graphics
Dim Drawbitmap As Bitmap
Dim Brush As New Drawing.SolidBrush(Color.Black)
private sub textbox1_text changed( byval sender as blah blah blah...)
Drawbitmap = New Bitmap(PictureBox1.Width, PictureBox1.Height)
Graph = Graphics.FromImage(Drawbitmap)
PictureBox1.Image = Drawbitmap
Graph.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
Graph.DrawString(TextBox1.Text, TextBox1.Font, Brush, PictureBox1.Location)
end sub