Private Declare Function GetBitmapBits Lib "gdi32" _
    (ByVal hBitmap As Long, ByVal dwCount As Long, _
    lpBits As Any) As Long


Private Declare Function GetObject Lib "gdi32" Alias _
    "GetObjectA" (ByVal hObject As Long, ByVal nCount _
    As Long, lpObject As Any) As Long

Private Type BITMAP
      bmType As Long
      bmWidth As Long
      bmHeight As Long
      bmWidthBytes As Long
      bmPlanes As Integer
      bmBitsPixel As Integer
      bmBits As Long
End Type


Private Function GetBitmapData(pic As PictureBox) As String

      Dim tBitmap As BITMAP
      Dim bPicBytes() As Byte
      Dim lByteLen As Long
      Dim lBytesPerLine As Long

      GetObject Picture1.Image.Handle, Len(tBitmap), tBitmap

      lBytesPerLine = (tBitmap.bmWidth * 4)
      lByteLen = lBytesPerLine * tBitmap.bmHeight
      ReDim bPicBytes(1 To lByteLen)
      GetBitmapBits pic.Picture.Handle, UBound(bPicBytes), bPicBytes(1)
      
      GetBitmapData = bPicBytes
End Function

Private Sub Form_Load()
MsgBox GetBitmapData(Picture1) = GetBitmapData(Picture2)
End Sub