No.17788
>>17786Try opening it in Paint.NET, saving it as a PNG, and setting the bit depth to 8-bit
This is what I usually do when I'm messing with RPG Maker 2003 stuff
No.17790
Using Paint.NET to save in 8bit works but it sometimes messes up the transparent color. Paint.NET doesn't have a palette viewer unfortunately. Personally I use GIMP to move the intended transparent color to index 0, making it transparent in RPG Maker.
There's this tool that sets transparent color, and can be used to modify images in batch. I don't know if it fixes the 256 color issue or not. Maybe it can still help you or anyone else who sees this thread.
https://github.com/lpre-ys/magic-pot-gui/releases