put the image transparent(not the backcolor, but the entire image)

i have these timer:

Code:

---

Private Sub tmrAnimation_Timer()
    If blnDestroyed = True Then
        tmrAnimation.Enabled = False
        Exit Sub
    End If
    On Error GoTo erro
    Const Transparency = (50 * 255) / 100 * &H10000 ' these number is for showing 50% of image
    If lngActualSubImage < PicAnimation.Count - 1 Then
        lngActualSubImage = lngActualSubImage + 1
    Else
        If Strip.Activate = True Then
            lngActualSubImage = 1
        Else
            lngActualSubImage = 0
        End If
    End If
    Set UserControl.Picture = Nothing
    UserControl.Cls
    If blnStretch = True Then
        StretchBlt UserControl.hdc, 0, 0, UserControl.ScaleWidth, UserControl.ScaleHeight, PicAnimation(lngActualSubImage).hdc, 0, 0, PicAnimation(lngActualSubImage).Width, PicAnimation(lngActualSubImage).Height, vbSrcCopy
    ElseIf blnAlphaBlend = True Then
        AlphaBlend UserControl.hdc, 0, 0, UserControl.ScaleWidth, UserControl.ScaleHeight, PicAnimation(lngActualSubImage).hdc, 0, 0, _
PicAnimation(lngActualSubImage).ScaleWidth, PicAnimation(lngActualSubImage).ScaleHeight, Transparency
    Else
        UserControl.Picture = PicAnimation(lngActualSubImage).Image
    End If
    If blnTransparent = True Then Call SubTransparent
    tmrAnimation.Enabled = False
    RaiseEvent ChangeImage(lngActualSubImage)
    tmrAnimation.Enabled = True
    Exit Sub
erro:
    tmrAnimation.Enabled = False
    MsgBox Err.Description
End Sub

---

i'm using the AlphBleng() API function for try put the image transparent, but doesn't work... i can't see the image back(the image back is a picturebox image)...
heres the image for show the problem... the problem is showed in Other Normal Images section...
can anyone tell me what isn't right?
thanks