How to get the pixel and chek them for a pirticular color

[Kirun]

i m making a digital image processing assigment.
what i want is that i have to draw a closed selection on
a picture in a picture box..

this i have done ..but i need that all color inside
the selction then would be black and out side the selection would be white..

but i am puzzeled how to do it .. can n e one willing
to help me i m writing my code .

I m drawing the line in a perticular color and cheking it in a function mask that if this perticualr combination of color exist then till another this type of color exist make the color black i.e 0 else every other thing is black.. but its not working..

Private Sub Picture1_MouseMove(Button As Integer, Shift As Integer, x As Single, Y As Single)
    If Button = 1 Then Picture1.Line (A, B)-(x, Y), RGB(100, 195, 155)
    A = x: B = Y
End Sub
 
Private Sub Picture1_MouseUp(Button As Integer, Shift As Integer, x As Single, Y As Single)
    If Button = 1 Then Picture1.Line (x, Y)-(x + 15, Y + 15)
End Sub
 
Private Sub mask(ByVal picColor As PictureBox)
    Picture2 = Picture1
 Dim x, Y, countz As Integer
 Dim red, green, blue, gray As Byte
    GetObject picColor.Image, Len(bm), bm
    wid = bm.BMPWidth
    hgt = bm.BMPHeight
    ReDim bytes(0 To bm.BMPWidthBytes - 1, 0 To hgt - 1)
    GetBitmapBits picColor.Image, bm.BMPWidthBytes * bm.BMPHeight, bytes(0, 0)
 
ProgressBar1.Min = 0
ProgressBar1.Max = hgt - 1
    ' Convert the data to gray scale.
    For Y = 0 To hgt - 1
        For x = 0 To wid - 1 Step 3
            ' Get the current pixel value.
            red = bytes(x * 3, Y)
            green = bytes(x * 3 + 1, Y)
            blue = bytes(x * 3 + 2, Y)
            While (red = 100) And (green = 195) And (blue = 155)
            bytes(x * 3, Y) = 0
            bytes(x * 3 + 1, Y) = 0
            bytes(x * 3 + 2, Y) = 0
            Wend
            bytes(x * 3, Y) = 255
            bytes(x * 3 + 1, Y) = 255
            bytes(x * 3 + 2, Y) = 255
            Next x
            ProgressBar1.Value = Y
        Next Y
 
    ' Set the new pixel values.
    SetBitmapBits picColor.Image, _
    bm.BMPWidthBytes * bm.BMPHeight, bytes(0, 0)
    picColor.Picture = picColor.Image
 
 
End Sub