Failing that, here's some code you can use to change one or more colors in
a bitmap...

You can do this by using GetDIBits() to get what is essentially a binary
copy of the device-independent bitmap into memory, changing the palette,
and using SetDIBits() to blast it back into the picturebox.

You'll want the picturebox.autoredraw = true, and scalemode = 3 (pixel).
This routine is specifically for 16-color bitmaps

Private Type BITMAPINFOHEADER   '40 bytes
   biSize As Long
   biWidth As Long
   biHeight As Long
   biPlanes As Integer
   biBitCount As Integer
   biCompression As Long
   biSizeImage As Long
   biXPel{*filter*}eter As Long
   biYPel{*filter*}eter As Long
   biClrUsed As Long
   biClrImportant As Long
End Type

Private Type RGBQUAD
   rgbBlue As Byte
   rgbGreen As Byte
   rgbRed As Byte
   rgbReserved As Byte
End Type

Private Type BITMAPINFO_4
   bmiHeader As BITMAPINFOHEADER
   bmiColors(15) As RGBQUAD
End Type

Private Const PIXEL As Integer = 3
Private Const DIB_RGB_COLORS As Long = 0

Private Declare Function GetDIBits4 Lib "gdi32" Alias "GetDIBits" _
  (ByVal aHDC As Long, ByVal hBitmap As Long, ByVal nStartScan As Long, _
  ByVal nNumScans As Long, lpBits As Any, lpBI As BITMAPINFO_4, _
  ByVal wUsage As Long) As Long

Private Declare Function SetDIBits4 Lib "gdi32" Alias "SetDIBits" _
  (ByVal hdc As Long, ByVal hBitmap As Long, ByVal nStartScan As Long, _
  ByVal nNumScans As Long, lpBits As Any, lpBI As BITMAPINFO_4, _
  ByVal wUsage As Long) As Long

    'size a buffer for the pixel data
    BufferSize = ((pic.ScaleWidth / 2 + 3) And &HFFFC) * pic.ScaleHeight
    ReDim SaveBits(0 To BufferSize - 1)
    'fill the header info for the save copy
    With SaveBitmapInfo_4.bmiHeader
        .biSize = 40
        .biWidth = pic.ScaleWidth
        .biHeight = pic.ScaleHeight
        .biPlanes = 1
        .biBitCount = 4
        .biCompression = 0
        .biClrUsed = 0
        .biClrImportant = 0
        .biSizeImage = BufferSize
    End With
    nLen = Len(SaveBitmapInfo_4)
    'get the bitmap from the picturebox
    Retval = GetDIBits4(pic.hdc, pic.Image, 0, _
        SaveBitmapInfo_4.bmiHeader.biHeight, SaveBits(0), SaveBitmapInfo_4,
DIB_RGB_COLORS)

    'change the palette
    SaveBitmapInfo_4.bmiColors(0).rgbRed = 255
    SaveBitmapInfo_4.bmiColors(0).rgbGreen = 255
    SaveBitmapInfo_4.bmiColors(0).rgbBlue = 0
    'blast it back in
    Retval = SetDIBits4(pic.hdc, pic.Image.Handle, 0, _
        SaveBitmapInfo_4.bmiHeader.biHeight, SaveBits(0), SaveBitmapInfo_4,
DIB_RGB_COLORS)
    pic.Refresh

It'll work most predictably if the original image has a standard palette.
Probably, if you want to change a particular color, you'll do best to
search the palette for it (I believe the light/dark grays have different
palette indices in Win95/NT).

Jim Deutch
MS Dev MVP