I have this form (form1)
I also want to have this graph(could someone suggest a good control
for this?)
I also have this picture (picture1)

What I want to do is place the picture on top of the graph, so that
people could select certain points on the picture (without knowing
there is a graph underneath), and then I need my program to use the
distance formula:
    _____________________
D=\/((X1-X2)^2+(Y1-Y2)^2)

to find out how far the two points are on the graph (but it looks like
the user has clicked on the picture)

I also want to know how I can superimpose a small, green square where
the user has clicked, and connect the lines in the order they were
clicked

Option Explicit
Private Type POINTAPI
    X As Long
    Y As Long
End Type

Private Sub Form_Load()
    With Picture1
        .ScaleMode = vbPixels
    End With

End Sub

Private Sub Picture1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
Static PreviousCoords As POINTAPI, bFirstPoint As Boolean
'Do something here is starting/stopping the line drawing

Load Shape1(Shape1.Count + 1)
With Shape1(Shape1.Count)
    .BorderColor = vbGreen
    .FillColor = vbGreen
    .Height = 3
    .Width = 3
    .Top = Y - 1
    .Left = X - 1
    .Visible = True
End With
If Not bFirstPoint Then
    bFirstPoint = True
Else
    Picture1.Line (PreviousCoords.X, PreviousCoords.Y)- _
            (X, Y), vbGreen
End If
PreviousCoords.X = X
PreviousCoords.Y = Y

End Sub

Mike

Thanks for the help....I will try that now

At the end of this you'll find some code, copy it into a forms code portion
and it should work fine.  Its very sloppy and a complete bodge but it should
give you some inspiration or at least help you assertain what you want. The
left button creates new points, the right button moves points (when you drag
the green square) and the escape button clears all points. Enjoy:-

Option Explicit

Private Type Point
   x As Long
   y As Long
End Type

Const MAXPOINTS = 32
Private Data(MAXPOINTS) As Point
Private NumPoints As Long
Private Pix As Long
Private Current As Long

Private Sub Form_KeyPress(KeyAscii As Integer)
   If KeyAscii = 27 Then
      NumPoints = 0
      Refresh
   End If
End Sub

Private Sub Form_Load()
   Current = -1
   Pix = 4 * ScaleX(1, vbPixels, ScaleMode)
   Picture = LoadPicture("C:\WINDOWS\Setup.bmp")
   ForeColor = RGB(191, 0, 0)
   FontTransparent = False
   DrawWidth = 2
End Sub

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, x As Single,
y As Single)
   Static OldX As Long
   Static OldY As Long
   Dim i As Long
   Select Case Button
      Case 0
         If Current <> -1 Then
            Data(Current).x = Data(Current).x + x - OldX
            Data(Current).y = Data(Current).y + y - OldY
            Current = -1
         End If
      Case 1: Current = CreatePoint(x, y)
      Case 2
         i = 0
         Current = -1
         While i < NumPoints And Current = -1
            If Abs(x - Data(i).x) <= Pix And Abs(y - Data(i).y) <= Pix Then
Current = i
            i = i + 1
         Wend
         OldX = x: OldY = y
   End Select
   Refresh
End Sub

Private Sub Form_MouseUp(Button As Integer, Shift As Integer, x As Single, y
As Single)
   If Button = 2 Then Form_MouseDown 0, Shift, x, y
End Sub

Private Function CreatePoint(ByVal x As Long, ByVal y As Long)
   If NumPoints < MAXPOINTS Then
      Current = NumPoints
      NumPoints = NumPoints + 1
      Data(Current).x = x
      Data(Current).y = y
   Else
      Beep
      Current = -1
   End If
End Function

At the end of this you'll find some code, copy it into a forms code portion
and it should work fine.  Its very sloppy and a complete bodge but it should
give you some inspiration or at least help you assertain what you want. The
left button creates new points, the right button moves points (when you drag
the green square) and the escape button clears all points. Enjoy:-

Option Explicit

Private Type Point
   x As Long
   y As Long
End Type

Const MAXPOINTS = 32
Private Data(MAXPOINTS) As Point
Private NumPoints As Long
Private Pix As Long
Private Current As Long

Private Sub Form_KeyPress(KeyAscii As Integer)
   If KeyAscii = 27 Then
      NumPoints = 0
      Refresh
   End If
End Sub

Private Sub Form_Load()
   Current = -1
   Pix = 4 * ScaleX(1, vbPixels, ScaleMode)
   Picture = LoadPicture("C:\WINDOWS\Setup.bmp")
   ForeColor = RGB(191, 0, 0)
   FontTransparent = False
   DrawWidth = 2
End Sub

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, x As Single,
y As Single)
   Static OldX As Long
   Static OldY As Long
   Dim i As Long
   Select Case Button
      Case 0
         If Current <> -1 Then
            Data(Current).x = Data(Current).x + x - OldX
            Data(Current).y = Data(Current).y + y - OldY
            Current = -1
         End If
      Case 1: Current = CreatePoint(x, y)
      Case 2
         i = 0
         Current = -1
         While i < NumPoints And Current = -1
            If Abs(x - Data(i).x) <= Pix And Abs(y - Data(i).y) <= Pix Then
Current = i
            i = i + 1
         Wend
         OldX = x: OldY = y
   End Select
   Refresh
End Sub

Private Sub Form_MouseUp(Button As Integer, Shift As Integer, x As Single, y
As Single)
   If Button = 2 Then Form_MouseDown 0, Shift, x, y
End Sub

Private Function CreatePoint(ByVal x As Long, ByVal y As Long)
   If NumPoints < MAXPOINTS Then
      Current = NumPoints
      NumPoints = NumPoints + 1
      Data(Current).x = x
      Data(Current).y = y
   Else
      Beep
      Current = -1
   End If
End Function