不是的
我的代码如下
Imports System.Drawing.Imaging
Imports System.IO
Imports System.Drawing
Public Class Form1
Dim g As Graphics
Dim p As New Pen(Color.Blue, 5)
Dim x, y As Integer
Dim bmp As Bitmap

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'g = Me.PictureBox1.CreateGraphics
bmp = New Bitmap(Me.PictureBox1.ClientSize.Width, Me.PictureBox1.ClientSize.Height)
PictureBox1.BackgroundImage = bmp
g = Graphics.FromImage(bmp)

End Sub

Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
x = e.X
y = e.Y
End Sub

Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
g = Me.PictureBox1.CreateGraphics
g.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
If e.Button = Windows.Forms.MouseButtons.Left Then
g.DrawLine(p, x, y, e.X, e.Y)
x = e.X
y = e.Y

End If
End Sub

Private Sub 保存SToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 保存SToolStripMenuItem.Click

With Me.SaveFileDialog1
.Title = "保存"
.Filter = "jpg(*.jpg)|*.jpg|所有文件(*.*)|*.*"
End With
If Me.SaveFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK And _
Me.SaveFileDialog1.FileName.Length > 0 Then

bmp.Save(Me.SaveFileDialog1.FileName)
End If

End Sub
End Class

请帮我看看