If you complete the game, and you complete it with more levels later. You will see new levels' screenshots with a "NEW" picture marking in ending staffroll anime.

I found that "NEW" picture will change screenshot file's first 4 boxes of palette.

So when importing all bitmaps with all palettes, maybe creating the palette since 5th box is better. Or I can change all same color on the picture with bucket fill (filling it discontinuously like in photoshop).

I prefer the first way (creating since 5th box). But I don't know how to do it in nsmbe. Or is there another software to edit the .enpg file which allows me to do this?