avoid overlapping of pictureboxes

Public Class Form1
    Dim pic1, pic2 As Rectangle
    Dim drag, iscollided As Boolean
    Dim mousex, mousey As Integer

    Private Sub pic_Mousemove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        If drag Then
            Dim mposition As New Point()
            mposition = Me.PointToClient(MousePosition)
            mposition.Offset(mousex, mousey)
            sender.location = mposition
        End If
    End Sub

    Private Sub pic_Mouseup(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        drag = False
        Windows.Forms.Cursor.Clip = Nothing
        Me.Cursor = Cursors.Arrow
        sender.invalidate()
    End Sub

    Private Sub pic_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        If e.Button = Windows.Forms.MouseButtons.Left Then
            Me.Cursor = Cursors.Hand
            drag = True
            mousex = -e.X
            mousey = -e.Y
            Dim left As Integer = Me.PointToClient(MousePosition).X - sender.location.x
            Dim right As Integer = Me.PointToClient(MousePosition).Y - sender.location.y
            Dim width As Integer = Me.ClientSize.Width - (sender.width - left)
            Dim height As Integer = Me.ClientSize.Height - (sender.width - right)
            Windows.Forms.Cursor.Clip = Me.RectangleToScreen(New Rectangle(left, right, width, height))
            sender.invalidate()
        End If
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        pic1.Location = PictureBox1.Location
        pic2.Location = PictureBox2.Location
        pic1.Size = PictureBox1.Size
        pic2.Size = PictureBox2.Size
        PictureBox1.SendToBack()
        PictureBox2.SendToBack()
        iscollided = CheckCollision()
        If iscollided = True Then
            PictureBox1.BackColor = Color.Transparent
        Else
            PictureBox1.BackColor = Color.Black
        End If
        Me.Text = iscollided.ToString
        AddHandler PictureBox1.MouseDown, AddressOf pic_MouseDown
        AddHandler PictureBox1.MouseMove, AddressOf pic_Mousemove
        AddHandler PictureBox1.MouseUp, AddressOf pic_Mouseup
        AddHandler PictureBox2.MouseDown, AddressOf pic_MouseDown
        AddHandler PictureBox2.MouseMove, AddressOf pic_Mousemove
        AddHandler PictureBox2.MouseUp, AddressOf pic_Mouseup

    End Sub


    Public Function CheckCollision()
        Dim result As Boolean = False
        If pic1.IntersectsWith(pic2) Then
            result = True
        Else
            result = False
        End If
        Return result
    End Function
End Class