method append_image ?(scale:((int*int) option)=None) filename =
begin
let pixbuf = GdkPixbuf.from_file filename in
let pixbuf = (match scale with
| None -> pixbuf
| Some (width,height) -> let scaled = GdkPixbuf.create ~has_alpha:true ~width ~height () in
GdkPixbuf.scale ~dest:scaled ~width ~height ~interp:`BILINEAR pixbuf; scaled) in
buffer#insert_pixbuf ~iter:iter ~pixbuf
end