Best Fade Method

I am trying to fade between two pictures. They each have their own Picture box and i am updating a third that contains the fading. I am using GetPixel and SetPixel, but it is really slow. Are there any faster methods of fading?

Thanks
-George

Create a Slider and set the min to 0 and the mex to 255
this code will fade the picture1 and picture3 into picture2

VB Code:

Option Explicit
Const AC_SRC_OVER = &H0
Private Type BLENDFUNCTION
  BlendOp As Byte
  BlendFlags As Byte
  SourceConstantAlpha As Byte
  AlphaFormat As Byte
End Type
Private Declare Function AlphaBlend Lib "msimg32.dll" (ByVal hdc As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal hdc As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal lInt As Long, ByVal BLENDFUNCT As Long) As Long
Private Declare Sub RtlMoveMemory Lib "kernel32.dll" (Destination As Any, Source As Any, ByVal Length As Long)
Private Sub Slider1_Change()
    Dim BF As BLENDFUNCTION, lBF As Long
    Picture2.Picture = Picture3.Picture
    'set the parameters
    With BF
        .BlendOp = AC_SRC_OVER
        .BlendFlags = 0
        .SourceConstantAlpha = Slider1.Value
        .AlphaFormat = 0
    End With
    'copy the BLENDFUNCTION-structure to a Long
    RtlMoveMemory lBF, BF, 4
    AlphaBlend Picture2.hdc, 0, 0, Picture2.ScaleWidth, Picture2.ScaleHeight, Picture1.hdc, 0, 0, Picture1.ScaleWidth, Picture1.ScaleHeight, lBF
    Picture2.Refresh
    
End Sub