procedure ConvertWMF2BMP
  (const WMFFileName, BMPFileName: TFileName);
var
  MetaFile: TMetafile;
  Bitmap: TBitmap;
begin
  Metafile := TMetaFile.Create;
  Bitmap := TBitmap.Create;
  try
    MetaFile.LoadFromFile(WMFFileName);
    with Bitmap do
    begin
      Height := Metafile.Height;
      Width := Metafile.Width;
      Canvas.Draw(0, 0, MetaFile);
      SaveToFile(BMPFileName);
    end;
  finally
    Bitmap.Free;
    MetaFile.Free;
  end;
end;

// Использование:
ConvertWMF2BMP('c:\mypic.wmf', 'c:\mypic.bmp')