Рисование на picturebox и сохранение в файл

Public Class Form1
 
    Dim x, y, x1, y1 As Single
    Dim g As Graphics
 
    ' получаем начальные координаты мышки при нажатии
    Private Sub PictureBox1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        If e.Button = MouseButtons.Left Then
            x = e.X
            y = e.Y
        End If
    End Sub
 
    ' рисуем линию от первых координат до текущих
    Private Sub PictureBox1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
        If e.Button = MouseButtons.Left Then
            x1 = e.X
            y1 = e.Y
            g.DrawLine(Pens.Red, x, y, x1, y1)
            x = x1
            y = y1
        End If
    End Sub
 
    ' цвет, курсор облости рисования
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        g = PictureBox1.CreateGraphics()
        PictureBox1.BackColor = Color.White
        PictureBox1.Cursor = Cursors.Cross
    End Sub
 
    ' преобразуем в Image и сохраняем, нашел в гугл :)
    Private Declare Ansi Function BitBlt Lib "gdi32" (ByVal hDestDC As IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hSrcDC As IntPtr, ByVal xSrc As Integer, ByVal ySrc As Integer, ByVal dwRop As Integer) As Integer
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim hdc As IntPtr = g.GetHdc()
        Dim bm As New Bitmap(PictureBox1.Width, PictureBox1.Height, Imaging.PixelFormat.Format24bppRgb)
        Dim bi As Graphics = Graphics.FromImage(bm)
        Dim hdc2 As IntPtr = bi.GetHdc()
        BitBlt(hdc2, 0, 0, PictureBox1.Width, PictureBox1.Height, hdc, 0, 0, &HCC0020&)
        bi.ReleaseHdc(hdc2)
        bi.Dispose()
        g.ReleaseHdc(hdc)
        bm.Save("c:\1.bmp", Imaging.ImageFormat.Bmp)
        bm.Dispose()
    End Sub
 
    ' очищяем Picturebox
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        g.FillRectangle(Brushes.White, 0, 0, PictureBox1.Width, PictureBox1.Height)
    End Sub
End Class