Making Colored Background on BMP Images Transparent (User Control Question)

I do have the User Control from a previous Visual Basic 6.0 project that allows certain colors to become transparent. But what I'd like to find out is, how can I make a certain color combination transparent using a User Control in Visual Basic 2008 Express?

Can we see the code from the user control?

It's a bit lengthy, here goes...

Code:

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Private Sub UserControl_Initialize()
UserControl.BackStyle = 0
End Sub

'Initialize Properties for User Control
Private Sub UserControl_InitProperties()

End Sub

'Load property values from storage
Private Sub UserControl_ReadProperties(PropBag As PropertyBag)

    UserControl.MaskColor = m_MaskColor
    Set Picture = PropBag.ReadProperty("Picture", Nothing)
    UserControl.MaskColor = PropBag.ReadProperty("MaskColor", &H8000000F)
    Set MaskPicture = PropBag.ReadProperty("MaskPicture", Nothing)
    UserControl.ScaleHeight = PropBag.ReadProperty("ScaleHeight", 3600)
    UserControl.ScaleLeft = PropBag.ReadProperty("ScaleLeft", 0)
    UserControl.ScaleMode = PropBag.ReadProperty("ScaleMode", 1)
    UserControl.ScaleTop = PropBag.ReadProperty("ScaleTop", 0)
    UserControl.ScaleWidth = PropBag.ReadProperty("ScaleWidth", 4800)
End Sub

'Write property values to storage
Private Sub UserControl_WriteProperties(PropBag As PropertyBag)

    Call PropBag.WriteProperty("Picture", Picture, Nothing)
    Call PropBag.WriteProperty("MaskColor", UserControl.MaskColor, &H8000000F)
    Call PropBag.WriteProperty("MaskPicture", MaskPicture, Nothing)
    Call PropBag.WriteProperty("ScaleHeight", UserControl.ScaleHeight, 3600)
    Call PropBag.WriteProperty("ScaleLeft", UserControl.ScaleLeft, 0)
    Call PropBag.WriteProperty("ScaleMode", UserControl.ScaleMode, 1)
    Call PropBag.WriteProperty("ScaleTop", UserControl.ScaleTop, 0)
    Call PropBag.WriteProperty("ScaleWidth", UserControl.ScaleWidth, 4800)
End Sub

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,Picture
Public Property Get Picture() As Picture
Attribute Picture.VB_Description = "Returns/sets a graphic to be displayed in a control."
    Set Picture = UserControl.Picture
End Property

Public Property Set Picture(ByVal New_Picture As Picture)
    Set UserControl.Picture = New_Picture
    PropertyChanged "Picture"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,MaskColor
Public Property Get MaskColor() As Long
Attribute MaskColor.VB_Description = "Returns/sets the color that specifies transparent areas in the MaskPicture."
    MaskColor = UserControl.MaskColor
End Property

Public Property Let MaskColor(ByVal New_MaskColor As Long)
    UserControl.MaskColor() = New_MaskColor
    PropertyChanged "MaskColor"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,MaskPicture
Public Property Get MaskPicture() As Picture
Attribute MaskPicture.VB_Description = "Returns/sets the picture that specifies the clickable/drawable area of the control when BackStyle is 0 (transparent)."
    Set MaskPicture = UserControl.MaskPicture
End Property

Public Property Set MaskPicture(ByVal New_MaskPicture As Picture)
    Set UserControl.MaskPicture = New_MaskPicture
    PropertyChanged "MaskPicture"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,ScaleHeight
Public Property Get ScaleHeight() As Single
Attribute ScaleHeight.VB_Description = "Returns/sets the number of units for the vertical measurement of an object's interior."
    ScaleHeight = UserControl.ScaleHeight
End Property

Public Property Let ScaleHeight(ByVal New_ScaleHeight As Single)
    UserControl.ScaleHeight() = New_ScaleHeight
    PropertyChanged "ScaleHeight"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,ScaleLeft
Public Property Get ScaleLeft() As Single
Attribute ScaleLeft.VB_Description = "Returns/sets the horizontal coordinates for the left edges of an object."
    ScaleLeft = UserControl.ScaleLeft
End Property

Public Property Let ScaleLeft(ByVal New_ScaleLeft As Single)
    UserControl.ScaleLeft() = New_ScaleLeft
    PropertyChanged "ScaleLeft"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,ScaleMode
Public Property Get ScaleMode() As Integer
Attribute ScaleMode.VB_Description = "Returns/sets a value indicating measurement units for object coordinates when using graphics methods or positioning controls."
    ScaleMode = UserControl.ScaleMode
End Property

Public Property Let ScaleMode(ByVal New_ScaleMode As Integer)
    UserControl.ScaleMode() = New_ScaleMode
    PropertyChanged "ScaleMode"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,ScaleTop
Public Property Get ScaleTop() As Single
Attribute ScaleTop.VB_Description = "Returns/sets the vertical coordinates for the top edges of an object."
    ScaleTop = UserControl.ScaleTop
End Property

Public Property Let ScaleTop(ByVal New_ScaleTop As Single)
    UserControl.ScaleTop() = New_ScaleTop
    PropertyChanged "ScaleTop"
End Property

'WARNING! DO NOT REMOVE OR MODIFY THE FOLLOWING COMMENTED LINES!
'MappingInfo=UserControl,UserControl,-1,ScaleWidth
Public Property Get ScaleWidth() As Single
Attribute ScaleWidth.VB_Description = "Returns/sets the number of units for the horizontal measurement of an object's interior."
    ScaleWidth = UserControl.ScaleWidth
End Property

Public Property Let ScaleWidth(ByVal New_ScaleWidth As Single)
    UserControl.ScaleWidth() = New_ScaleWidth
    PropertyChanged "ScaleWidth"
End Property

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