Private Declare Function GetPixel& Lib "gdi32" (ByVal hdc&, ByVal x&, ByVal y&)
Private Declare Function SetPixelV& Lib "gdi32" (ByVal hdc&, ByVal x&, ByVal _
  y&, ByVal crColor&)
 
Private Sub Command1_Click()
 
  Dim x1&, y1&, Color1&, R&, G&, B&, Grenzwert&, Pic1hdc&
 
  Grenzwert = 128
  With Picture1
    .ScaleMode = vbPixels
    .AutoRedraw = True
    Pic1hdc = .hdc
    For y1 = 0 To .ScaleHeight - 1
      For x1 = 0 To .ScaleWidth - 1
        Color1 = GetPixel(Pic1hdc, x1, y1)
        R = Color1 And vbRed
        G = (Color1 And vbGreen) \ &H100
        B = (Color1 And vbBlue) \ &H10000
        If R < Grenzwert And G < Grenzwert And B < Grenzwert Then
          Call SetPixelV(Pic1hdc, x1, y1, vbBlack)
        End If
      Next x1
      DoEvents
    Next y1
    .Refresh
  End With
 
End Sub

Gruss,

Zardoz