[RESOLVED] picturebox problem

I have this code which creates a picturebox during runtime and displays line graph but I always get an error in this line:

gr1.DrawImage(pic1.Image, -m_Dx, 0) 'it says Value cannot be null. Parameter name: image

code Code:

Public Class Form1
    Private Const m_Dx As Single = 1
    Dim data As Integer = 1
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim pic1 As New PictureBox
        pic1.Location = New Point(12, 12)
        pic1.Name = "pic1"
        pic1.Width = 142
        pic1.Height = 102
        pic1.Visible = True
        pic1.BackColor = Color.Black
        pic1.BorderStyle = BorderStyle.Fixed3D
 
        Controls.Add(pic1)
 
        Dim bm1 As New Bitmap(pic1.Width, pic1.Height)
        Dim gr1 As Graphics = Graphics.FromImage(bm1)
        gr1.DrawImage(pic1.Image, -m_Dx, 0)
 
        gr1.ScaleTransform(1, -101 / pic1.Height)
        gr1.TranslateTransform(0, -101)
 
        Dim new_value1 As Integer = Val(data) / 2
 
        If new_value1 < 1 Then new_value1 = 1
        gr1.DrawLine(Pens.Blue, _
            pic1.Width - 1, 0, _
            pic1.Width - 1, new_value1)
 
        For i As Integer = 20 To 80 Step 20
            gr1.DrawLine(Pens.Red, pic1.Width - m_Dx, i, pic1.Width, i)
        Next i
 
        pic1.Image = bm1
 
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        data = data + 1
    End Sub
End Class

Did I miss something?