Photoshop png Indexed Images

[evmaster]

Hi. I was wondering if anyone knew how to make their sprites work in rpg maker 2003 by saving them as an indexed png in Photoshop. By work, I mean their background being automatically transparent without having to import the image and make it transparent. I think the part where you save it as an indexed image has to do with how it will appear in the game maker or not. That box that appears with options before you save it as a png.

Please note I know how to import images into my game. It's just the part of the colored box.

I am hoping someone might know here.

Thanks in advance.