Ok, did it like this:

//put a glplane onto the viewing area (orientate it so that it looks 2d) and assign a bitmap to it. Is there a faster way?

procedure TForm1.SpeedButton2Click(Sender: TObject);
var
rbitmap : tbitmap;
begin
rbitmap:=tbitmap.Create;
rbitmap.SetSize(200,200);
// glplane1.Material.Texture.Image.AssignToBitmap(rbi tmap);
glplane1.Material.Texture.Image.Assign(rbitmap);

end;