I've noticed when replacing some textures that the colors appear different from when you view an image in Windows as a PNG and when it's imported. I don't think there's any problem with the pngpal2raw-tool as it's importing all the existing textures correctly. Most of them appear as they do in-game except fo the Ghost that's much darker as PNG. I've also noticed it's mostly the color blue that appear the most noticeably off and there's really no creature with that much blue.
What I wonder really is if this effect can be explained and maybe emulated in Photoshop or GIMP? Red and green just seem a little darker but blue is more on the side of purple. I'm thinking just so I don't have to import a picture to see how the colors look.
I've attached an image of an image how it looks like as a PNG and in-game.