I have no use for an application like this but it seems to work pretty well for the images I tested. Something that I was surprised about was that despite not working in Wine, I was still able to get the demo version working in Linux through a different method. Even though this isn't a game, PixaTool was made in construct, which means that I was able to run this through Bakustarver's RPG Maker tool for Linux from GitHub and it seems to run well.