SEAFOODRAMEN'S PROFILE

I made a charset for a game in rm2k3 and it first said invalid color depth so I looked up tutorials and got Irfanview and followed the tutorials and then it was "unsupported png file" so i looked up help for that too. Nothing has worked so far. I have opened, edited, saved as a png and bmp this charset in several programs. I've tried MS Paint, Irfanview, Gimp, even Paint tool Sai. I have firealpaca, the only program so far on my computer I havent tried. I can get Photoshop if that's what it takes to fix this. I have no clue whats wrong with it, I have indexed the color, RBG-ed the color, I've set it to 256 colors and 16 colors, and I'm at my wits end! Any and all help is so greatly appreciated! I'm still quite new at this but I put a lot of work into it and would hate to waste it! Thank you!