draw a few lines on an image with mouse move

Question

I want to draw a few lines on an image Using mouse move in vb.net. My problem is that when I start drawing the next line, the previous line disappears! Can anyone help me? I put my code along with a photo of run my project.

 ![Dim st, en As New Point  
    Dim p As Pen  
    Private mouseButtonPressed As Boolean = False  
  
    Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint  
        p = New Pen(Color.Black, 2)  
        Dim g As Graphics = e.Graphics  
        g.DrawLine(p, st, en)  
    End Sub  
  
    Private Sub PictureBox1_MouseUp(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseUp  
        mouseButtonPressed = False  
    End Sub  
  
    Private Sub PictureBox1_MouseMove(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseMove  
        If mouseButtonPressed Then  
            PictureBox1.Invalidate()  
            en = e.Location  
        End If  
    End Sub  
  
    Private Sub PictureBox1_MouseDown(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseDown  
        If e.Button = MouseButtons.Left Then  
            st = New Point(e.X, e.Y)  
            mouseButtonPressed = True  
        End If  
    End Sub][1]  

Answer 1

You can use the method from Let the user draw lines in C#

Public Class Form1        

    Private Segments As List(Of Segment) = New List(Of Segment)()
    Private NewSegment As Segment = Nothing

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

    Private Sub PictureBox1_MouseDown(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseDown
        NewSegment = New Segment(Pens.Blue, e.Location, e.Location)
        PictureBox1.Refresh()
    End Sub

    Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
        e.Graphics.Clear(PictureBox1.BackColor)
        e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias

        For Each segment As Segment In Segments
            segment.Draw(e.Graphics)
        Next

        If NewSegment IsNot Nothing Then NewSegment.Draw(e.Graphics)
    End Sub

    Private Sub PictureBox1_MouseMove(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseMove
        If NewSegment Is Nothing Then Return
        NewSegment.pt2 = e.Location
        PictureBox1.Refresh()
    End Sub

    Private Sub PictureBox1_MouseUp(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseUp
        If NewSegment Is Nothing Then Return
        NewSegment.pen1 = Pens.Black
        Segments.Add(NewSegment)
        NewSegment = Nothing
        PictureBox1.Refresh()
    End Sub
End Class

Class Segment
    Public pen1 As Pen
    Public pt1, pt2 As Point

    Public Sub New(pen As Pen, point1 As Point, point2 As Point)
        pen1 = pen
        pt1 = point1
        pt2 = point2
    End Sub

    Public Sub Draw(gr As Graphics)
        gr.DrawLine(pen1, pt1, pt2)
    End Sub
End Class

Answer 2

NOW HOW TO SAVE IMAGE with the drawn lines?