Passing variables...not understanding...

[BrianExcel]

I am using the following code which when run displays an image from a set of three.

Sub optInkColor_Click()
    ShowImageInk "imgInkColor"
End Sub

Sub optInkBW_Click()
    ShowImageInk "imgInkBW"
End Sub

Sub optInkMix_Click()
    ShowImageInk "imgInkMix"
End Sub

Sub ShowImageInk(whichOneink As String)

    Dim objImage As Image
    Dim cntl As Control

    For Each cntl In Me.frmInk.Controls
        If Left(cntl.Name, 3) = "img" Then
            cntl.Visible = False
        End If
    Next cntl

    Set objImage = Me.Controls(whichOneink)
    objImage.Visible = True

    Set objImage = Nothing
End Sub

I am trying to better understand how to pass variables to simplify code, and so I am trying to re-write the above code using different scenarios. For example: I have three buttons, and one label. Each button is named uniquely such as btn1, btn2, btn3 with different captions. What I want to do is display the caption of the button selected in the label, but I can't figure out what I am doing wrong.

Could someone please help with the requested code above? Or at the very least try to explain (for Dummies) how to pass variables? I know this should be simple but I am struggling with it...