The biggest Issue i have when using this tool is how much time i spend figuring out how to get images (from say textures.com) to end up scaled in multiples of 16, i wish this would just automate this process. essentially if an image is 517x261 it will just downscale it to 512z256 by just cropping out the excess.
i don't mind the potential problem of cropping out too much because that's an easy problem to fix that problably won't happen on most textures