Visual Basic.NET - Consulta sobre uso de "CreateGraphics"

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

        Dim w As Integer = 200

        Dim h As Integer = 200

        Dim bmp As New Bitmap(w, h)

        Dim g As Graphics

        g = Graphics.FromImage(bmp)

        g.Clear(Color.GreenYellow)

        g.SmoothingMode = Drawing2D.SmoothingMode.HighQuality

        g.CompositingQuality = Drawing2D.CompositingQuality.HighQuality

        g.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic

        g.TranslateTransform(CSng(w / 2), CSng(h / 2))

        g.ScaleTransform(0.5, -0.5)

        For x As Integer = -w To w Step 10

            g.DrawLine(Pens.Gray, x, -w, x, h)

        Next

        For y As Integer = -h To h Step 10

            g.DrawLine(Pens.Gray, -h, y, w, y)

        Next

        g.DrawLine(Pens.Black, 0, 0, 50, 50)

        g.FillEllipse(Brushes.Blue, -40, -20, 30, 30)

        Dim w2 As Integer = 200

        Dim h2 As Integer = 200

        Dim bmp2 As New Bitmap(w2, h2)

        Dim g2 As Graphics

        g2 = Graphics.FromImage(bmp2)

        g2.Clear(Color.Green)

        g2.SmoothingMode = Drawing2D.SmoothingMode.HighQuality

        g2.CompositingQuality = Drawing2D.CompositingQuality.HighQuality

        g2.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic

        g2.TranslateTransform(CSng(w2 / 2), CSng(h2 / 2))

        g2.ScaleTransform(1, -1)

        For x As Integer = -w2 To w2 Step 10

            g2.DrawLine(Pens.Gray, x, -w2, x, h2)

        Next

        For y As Integer = -h2 To h2 Step 10

            g2.DrawLine(Pens.Gray, -h2, y, w2, y)

        Next

        g2.DrawLine(Pens.Black, 0, 0, 50, 50)

        g2.FillEllipse(Brushes.Blue, -40, 60, 30, 30)

        Dim fg As Graphics

        fg = Me.CreateGraphics

        fg.DrawImage(bmp, 0, 0)

        fg.DrawImage(bmp2, w, 0)

    End Sub