Web Forms :: Converting Bitmap To Ehm.bitmap

I have a colorpicker.png file and track the pixel clicked in codebehind using GetPixel. Works like a charm, but I read that converting to a bitmap on the fly is rather heavy on the server. Therefore I saved my .png file as a .bmp as well, so that a converted file would already exist. However, I don't seem tobe able to just use the bitmap file, but need to create a new bitmap from the bitmap...

My question is: The code below works (I provide it here for those who might need it - simply add the code below to codebehind and this code in your aspx page <asp:ImageButton

ID="cpRubrik"
runat="server"
ImageUrl="~/img/colorpicker.png"
/> ;

also note that the image can be whatever you want - a photo or a screendump of a colorpicker from say Photoshop or VS; and note that it's wise to put everything you need in an updatepanel). Should I write something else in order to get smarter access to the bitmap?

Protected Sub cpRubrik_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles cpRubrik.Click
tbUtseenderub.ForeColor = BytFarg(e.X, e.Y)
End Sub
Protected Function BytFarg(ByVal x As Integer, ByVal y As Integer) As Color
Dim myBitmap As New Bitmap(Server.MapPath("~/img/colorpicker.bmp"))
Dim clr As Color = myBitmap.GetPixel(x, y)
Return clr
End Function